deps: update V8 to 5.5.372.40

PR-URL: https://github.com/nodejs/node/pull/9618
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

10 files changed, 1245 insertions, 206 deletions

diff --git a/deps/v8/include/DEPS b/deps/v8/include/DEPS
new file mode 100644
index 0000000000..ca60f841f5
--- /dev/null
+++ b/deps/v8/include/DEPS
@@ -0,0 +1,4 @@
+include_rules = [
+  # v8-inspector-protocol.h depends on generated files under include/inspector.
+  "+inspector",
+]
diff --git a/deps/v8/include/OWNERS b/deps/v8/include/OWNERS
index efa3b936d5..07f8a610c5 100644
--- a/deps/v8/include/OWNERS
+++ b/deps/v8/include/OWNERS
@@ -1,2 +1,7 @@
 danno@chromium.org
 jochen@chromium.org
+
+per-file v8-inspector.h=dgozman@chromium.org
+per-file v8-inspector.h=pfeldman@chromium.org
+per-file v8-inspector-protocol.h=dgozman@chromium.org
+per-file v8-inspector-protocol.h=pfeldman@chromium.org
diff --git a/deps/v8/include/libplatform/v8-tracing.h b/deps/v8/include/libplatform/v8-tracing.h
index 7646ea5489..e9f4941478 100644
--- a/deps/v8/include/libplatform/v8-tracing.h
+++ b/deps/v8/include/libplatform/v8-tracing.h
@@ -7,9 +7,17 @@
 
 #include <fstream>
 #include <memory>
+#include <unordered_set>
 #include <vector>
 
+#include "v8-platform.h"  // NOLINT(build/include)
+
 namespace v8 {
+
+namespace base {
+class Mutex;
+}  // namespace base
+
 namespace platform {
 namespace tracing {
 
@@ -28,19 +36,22 @@ class TraceObject {
 
   TraceObject() {}
   ~TraceObject();
-  void Initialize(char phase, const uint8_t* category_enabled_flag,
-                  const char* name, const char* scope, uint64_t id,
-                  uint64_t bind_id, int num_args, const char** arg_names,
-                  const uint8_t* arg_types, const uint64_t* arg_values,
-                  unsigned int flags);
+  void Initialize(
+      char phase, const uint8_t* category_enabled_flag, const char* name,
+      const char* scope, uint64_t id, uint64_t bind_id, int num_args,
+      const char** arg_names, const uint8_t* arg_types,
+      const uint64_t* arg_values,
+      std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
+      unsigned int flags);
   void UpdateDuration();
-  void InitializeForTesting(char phase, const uint8_t* category_enabled_flag,
-                            const char* name, const char* scope, uint64_t id,
-                            uint64_t bind_id, int num_args,
-                            const char** arg_names, const uint8_t* arg_types,
-                            const uint64_t* arg_values, unsigned int flags,
-                            int pid, int tid, int64_t ts, int64_t tts,
-                            uint64_t duration, uint64_t cpu_duration);
+  void InitializeForTesting(
+      char phase, const uint8_t* category_enabled_flag, const char* name,
+      const char* scope, uint64_t id, uint64_t bind_id, int num_args,
+      const char** arg_names, const uint8_t* arg_types,
+      const uint64_t* arg_values,
+      std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
+      unsigned int flags, int pid, int tid, int64_t ts, int64_t tts,
+      uint64_t duration, uint64_t cpu_duration);
 
   int pid() const { return pid_; }
   int tid() const { return tid_; }
@@ -56,6 +67,9 @@ class TraceObject {
   const char** arg_names() { return arg_names_; }
   uint8_t* arg_types() { return arg_types_; }
   ArgValue* arg_values() { return arg_values_; }
+  std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables() {
+    return arg_convertables_;
+  }
   unsigned int flags() const { return flags_; }
   int64_t ts() { return ts_; }
   int64_t tts() { return tts_; }
@@ -71,10 +85,12 @@ class TraceObject {
   const uint8_t* category_enabled_flag_;
   uint64_t id_;
   uint64_t bind_id_;
-  int num_args_;
+  int num_args_ = 0;
   const char* arg_names_[kTraceMaxNumArgs];
   uint8_t arg_types_[kTraceMaxNumArgs];
   ArgValue arg_values_[kTraceMaxNumArgs];
+  std::unique_ptr<v8::ConvertableToTraceFormat>
+      arg_convertables_[kTraceMaxNumArgs];
   char* parameter_copy_storage_ = nullptr;
   unsigned int flags_;
   int64_t ts_;
@@ -217,21 +233,27 @@ class TracingController {
     ENABLED_FOR_ETW_EXPORT = 1 << 3
   };
 
-  TracingController() {}
+  TracingController();
+  ~TracingController();
   void Initialize(TraceBuffer* trace_buffer);
   const uint8_t* GetCategoryGroupEnabled(const char* category_group);
   static const char* GetCategoryGroupName(const uint8_t* category_enabled_flag);
-  uint64_t AddTraceEvent(char phase, const uint8_t* category_enabled_flag,
-                         const char* name, const char* scope, uint64_t id,
-                         uint64_t bind_id, int32_t num_args,
-                         const char** arg_names, const uint8_t* arg_types,
-                         const uint64_t* arg_values, unsigned int flags);
+  uint64_t AddTraceEvent(
+      char phase, const uint8_t* category_enabled_flag, const char* name,
+      const char* scope, uint64_t id, uint64_t bind_id, int32_t num_args,
+      const char** arg_names, const uint8_t* arg_types,
+      const uint64_t* arg_values,
+      std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
+      unsigned int flags);
   void UpdateTraceEventDuration(const uint8_t* category_enabled_flag,
                                 const char* name, uint64_t handle);
 
   void StartTracing(TraceConfig* trace_config);
   void StopTracing();
 
+  void AddTraceStateObserver(Platform::TraceStateObserver* observer);
+  void RemoveTraceStateObserver(Platform::TraceStateObserver* observer);
+
  private:
   const uint8_t* GetCategoryGroupEnabledInternal(const char* category_group);
   void UpdateCategoryGroupEnabledFlag(size_t category_index);
@@ -239,6 +261,8 @@ class TracingController {
 
   std::unique_ptr<TraceBuffer> trace_buffer_;
   std::unique_ptr<TraceConfig> trace_config_;
+  std::unique_ptr<base::Mutex> mutex_;
+  std::unordered_set<Platform::TraceStateObserver*> observers_;
   Mode mode_ = DISABLED;
 
   // Disallow copy and assign
diff --git a/deps/v8/include/v8-inspector-protocol.h b/deps/v8/include/v8-inspector-protocol.h
new file mode 100644
index 0000000000..612a2ebc39
--- /dev/null
+++ b/deps/v8/include/v8-inspector-protocol.h
@@ -0,0 +1,13 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_V8_INSPECTOR_PROTOCOL_H_
+#define V8_V8_INSPECTOR_PROTOCOL_H_
+
+#include "inspector/Debugger.h"  // NOLINT(build/include)
+#include "inspector/Runtime.h"   // NOLINT(build/include)
+#include "inspector/Schema.h"    // NOLINT(build/include)
+#include "v8-inspector.h"        // NOLINT(build/include)
+
+#endif  // V8_V8_INSPECTOR_PROTOCOL_H_
diff --git a/deps/v8/include/v8-inspector.h b/deps/v8/include/v8-inspector.h
new file mode 100644
index 0000000000..0855ac101b
--- /dev/null
+++ b/deps/v8/include/v8-inspector.h
@@ -0,0 +1,267 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_V8_INSPECTOR_H_
+#define V8_V8_INSPECTOR_H_
+
+#include <stdint.h>
+#include <cctype>
+
+#include <memory>
+
+#include "v8.h"  // NOLINT(build/include)
+
+namespace v8_inspector {
+
+namespace protocol {
+namespace Debugger {
+namespace API {
+class SearchMatch;
+}
+}
+namespace Runtime {
+namespace API {
+class RemoteObject;
+class StackTrace;
+}
+}
+namespace Schema {
+namespace API {
+class Domain;
+}
+}
+}  // namespace protocol
+
+class V8_EXPORT StringView {
+ public:
+  StringView() : m_is8Bit(true), m_length(0), m_characters8(nullptr) {}
+
+  StringView(const uint8_t* characters, size_t length)
+      : m_is8Bit(true), m_length(length), m_characters8(characters) {}
+
+  StringView(const uint16_t* characters, size_t length)
+      : m_is8Bit(false), m_length(length), m_characters16(characters) {}
+
+  bool is8Bit() const { return m_is8Bit; }
+  size_t length() const { return m_length; }
+
+  // TODO(dgozman): add DCHECK(m_is8Bit) to accessors once platform can be used
+  // here.
+  const uint8_t* characters8() const { return m_characters8; }
+  const uint16_t* characters16() const { return m_characters16; }
+
+ private:
+  bool m_is8Bit;
+  size_t m_length;
+  union {
+    const uint8_t* m_characters8;
+    const uint16_t* m_characters16;
+  };
+};
+
+class V8_EXPORT StringBuffer {
+ public:
+  virtual ~StringBuffer() {}
+  virtual const StringView& string() = 0;
+  // This method copies contents.
+  static std::unique_ptr<StringBuffer> create(const StringView&);
+};
+
+class V8_EXPORT V8ContextInfo {
+ public:
+  V8ContextInfo(v8::Local<v8::Context> context, int contextGroupId,
+                const StringView& humanReadableName)
+      : context(context),
+        contextGroupId(contextGroupId),
+        humanReadableName(humanReadableName),
+        hasMemoryOnConsole(false) {}
+
+  v8::Local<v8::Context> context;
+  // Each v8::Context is a part of a group. The group id must be non-zero.
+  int contextGroupId;
+  StringView humanReadableName;
+  StringView origin;
+  StringView auxData;
+  bool hasMemoryOnConsole;
+
+ private:
+  // Disallow copying and allocating this one.
+  enum NotNullTagEnum { NotNullLiteral };
+  void* operator new(size_t) = delete;
+  void* operator new(size_t, NotNullTagEnum, void*) = delete;
+  void* operator new(size_t, void*) = delete;
+  V8ContextInfo(const V8ContextInfo&) = delete;
+  V8ContextInfo& operator=(const V8ContextInfo&) = delete;
+};
+
+class V8_EXPORT V8StackTrace {
+ public:
+  virtual bool isEmpty() const = 0;
+  virtual StringView topSourceURL() const = 0;
+  virtual int topLineNumber() const = 0;
+  virtual int topColumnNumber() const = 0;
+  virtual StringView topScriptId() const = 0;
+  virtual StringView topFunctionName() const = 0;
+
+  virtual ~V8StackTrace() {}
+  virtual std::unique_ptr<protocol::Runtime::API::StackTrace>
+  buildInspectorObject() const = 0;
+  virtual std::unique_ptr<StringBuffer> toString() const = 0;
+
+  // Safe to pass between threads, drops async chain.
+  virtual std::unique_ptr<V8StackTrace> clone() = 0;
+};
+
+class V8_EXPORT V8InspectorSession {
+ public:
+  virtual ~V8InspectorSession() {}
+
+  // Cross-context inspectable values (DOM nodes in different worlds, etc.).
+  class V8_EXPORT Inspectable {
+   public:
+    virtual v8::Local<v8::Value> get(v8::Local<v8::Context>) = 0;
+    virtual ~Inspectable() {}
+  };
+  virtual void addInspectedObject(std::unique_ptr<Inspectable>) = 0;
+
+  // Dispatching protocol messages.
+  static bool canDispatchMethod(const StringView& method);
+  virtual void dispatchProtocolMessage(const StringView& message) = 0;
+  virtual std::unique_ptr<StringBuffer> stateJSON() = 0;
+  virtual std::vector<std::unique_ptr<protocol::Schema::API::Domain>>
+  supportedDomains() = 0;
+
+  // Debugger actions.
+  virtual void schedulePauseOnNextStatement(const StringView& breakReason,
+                                            const StringView& breakDetails) = 0;
+  virtual void cancelPauseOnNextStatement() = 0;
+  virtual void breakProgram(const StringView& breakReason,
+                            const StringView& breakDetails) = 0;
+  virtual void setSkipAllPauses(bool) = 0;
+  virtual void resume() = 0;
+  virtual void stepOver() = 0;
+  virtual std::vector<std::unique_ptr<protocol::Debugger::API::SearchMatch>>
+  searchInTextByLines(const StringView& text, const StringView& query,
+                      bool caseSensitive, bool isRegex) = 0;
+
+  // Remote objects.
+  virtual std::unique_ptr<protocol::Runtime::API::RemoteObject> wrapObject(
+      v8::Local<v8::Context>, v8::Local<v8::Value>,
+      const StringView& groupName) = 0;
+  virtual bool unwrapObject(std::unique_ptr<StringBuffer>* error,
+                            const StringView& objectId, v8::Local<v8::Value>*,
+                            v8::Local<v8::Context>*,
+                            std::unique_ptr<StringBuffer>* objectGroup) = 0;
+  virtual void releaseObjectGroup(const StringView&) = 0;
+};
+
+enum class V8ConsoleAPIType { kClear, kDebug, kLog, kInfo, kWarning, kError };
+
+class V8_EXPORT V8InspectorClient {
+ public:
+  virtual ~V8InspectorClient() {}
+
+  virtual void runMessageLoopOnPause(int contextGroupId) {}
+  virtual void quitMessageLoopOnPause() {}
+  virtual void runIfWaitingForDebugger(int contextGroupId) {}
+
+  virtual void muteMetrics(int contextGroupId) {}
+  virtual void unmuteMetrics(int contextGroupId) {}
+
+  virtual void beginUserGesture() {}
+  virtual void endUserGesture() {}
+
+  virtual std::unique_ptr<StringBuffer> valueSubtype(v8::Local<v8::Value>) {
+    return nullptr;
+  }
+  virtual bool formatAccessorsAsProperties(v8::Local<v8::Value>) {
+    return false;
+  }
+  virtual bool isInspectableHeapObject(v8::Local<v8::Object>) { return true; }
+
+  virtual v8::Local<v8::Context> ensureDefaultContextInGroup(
+      int contextGroupId) {
+    return v8::Local<v8::Context>();
+  }
+  virtual void beginEnsureAllContextsInGroup(int contextGroupId) {}
+  virtual void endEnsureAllContextsInGroup(int contextGroupId) {}
+
+  virtual void installAdditionalCommandLineAPI(v8::Local<v8::Context>,
+                                               v8::Local<v8::Object>) {}
+  virtual void consoleAPIMessage(int contextGroupId, V8ConsoleAPIType,
+                                 const StringView& message,
+                                 const StringView& url, unsigned lineNumber,
+                                 unsigned columnNumber, V8StackTrace*) {}
+  virtual v8::MaybeLocal<v8::Value> memoryInfo(v8::Isolate*,
+                                               v8::Local<v8::Context>) {
+    return v8::MaybeLocal<v8::Value>();
+  }
+
+  virtual void consoleTime(const StringView& title) {}
+  virtual void consoleTimeEnd(const StringView& title) {}
+  virtual void consoleTimeStamp(const StringView& title) {}
+  virtual double currentTimeMS() { return 0; }
+  typedef void (*TimerCallback)(void*);
+  virtual void startRepeatingTimer(double, TimerCallback, void* data) {}
+  virtual void cancelTimer(void* data) {}
+
+  // TODO(dgozman): this was added to support service worker shadow page. We
+  // should not connect at all.
+  virtual bool canExecuteScripts(int contextGroupId) { return true; }
+};
+
+class V8_EXPORT V8Inspector {
+ public:
+  static std::unique_ptr<V8Inspector> create(v8::Isolate*, V8InspectorClient*);
+  virtual ~V8Inspector() {}
+
+  // Contexts instrumentation.
+  virtual void contextCreated(const V8ContextInfo&) = 0;
+  virtual void contextDestroyed(v8::Local<v8::Context>) = 0;
+  virtual void resetContextGroup(int contextGroupId) = 0;
+
+  // Various instrumentation.
+  virtual void willExecuteScript(v8::Local<v8::Context>, int scriptId) = 0;
+  virtual void didExecuteScript(v8::Local<v8::Context>) = 0;
+  virtual void idleStarted() = 0;
+  virtual void idleFinished() = 0;
+
+  // Async stack traces instrumentation.
+  virtual void asyncTaskScheduled(const StringView& taskName, void* task,
+                                  bool recurring) = 0;
+  virtual void asyncTaskCanceled(void* task) = 0;
+  virtual void asyncTaskStarted(void* task) = 0;
+  virtual void asyncTaskFinished(void* task) = 0;
+  virtual void allAsyncTasksCanceled() = 0;
+
+  // Exceptions instrumentation.
+  virtual unsigned exceptionThrown(
+      v8::Local<v8::Context>, const StringView& message,
+      v8::Local<v8::Value> exception, const StringView& detailedMessage,
+      const StringView& url, unsigned lineNumber, unsigned columnNumber,
+      std::unique_ptr<V8StackTrace>, int scriptId) = 0;
+  virtual void exceptionRevoked(v8::Local<v8::Context>, unsigned exceptionId,
+                                const StringView& message) = 0;
+
+  // Connection.
+  class V8_EXPORT Channel {
+   public:
+    virtual ~Channel() {}
+    virtual void sendProtocolResponse(int callId,
+                                      const StringView& message) = 0;
+    virtual void sendProtocolNotification(const StringView& message) = 0;
+    virtual void flushProtocolNotifications() = 0;
+  };
+  virtual std::unique_ptr<V8InspectorSession> connect(
+      int contextGroupId, Channel*, const StringView& state) = 0;
+
+  // API methods.
+  virtual std::unique_ptr<V8StackTrace> createStackTrace(
+      v8::Local<v8::StackTrace>) = 0;
+  virtual std::unique_ptr<V8StackTrace> captureStackTrace(bool fullStack) = 0;
+};
+
+}  // namespace v8_inspector
+
+#endif  // V8_V8_INSPECTOR_H_
diff --git a/deps/v8/include/v8-platform.h b/deps/v8/include/v8-platform.h
index 4023a5b234..e11567488b 100644
--- a/deps/v8/include/v8-platform.h
+++ b/deps/v8/include/v8-platform.h
@@ -7,6 +7,8 @@
 
 #include <stddef.h>
 #include <stdint.h>
+#include <memory>
+#include <string>
 
 namespace v8 {
 
@@ -17,24 +19,38 @@ class Isolate;
  */
 class Task {
  public:
-  virtual ~Task() {}
+  virtual ~Task() = default;
 
   virtual void Run() = 0;
 };
 
-
 /**
-* An IdleTask represents a unit of work to be performed in idle time.
-* The Run method is invoked with an argument that specifies the deadline in
-* seconds returned by MonotonicallyIncreasingTime().
-* The idle task is expected to complete by this deadline.
-*/
+ * An IdleTask represents a unit of work to be performed in idle time.
+ * The Run method is invoked with an argument that specifies the deadline in
+ * seconds returned by MonotonicallyIncreasingTime().
+ * The idle task is expected to complete by this deadline.
+ */
 class IdleTask {
  public:
-  virtual ~IdleTask() {}
+  virtual ~IdleTask() = default;
   virtual void Run(double deadline_in_seconds) = 0;
 };
 
+/**
+ * The interface represents complex arguments to trace events.
+ */
+class ConvertableToTraceFormat {
+ public:
+  virtual ~ConvertableToTraceFormat() = default;
+
+  /**
+   * Append the class info to the provided |out| string. The appended
+   * data must be a valid JSON object. Strings must be properly quoted, and
+   * escaped. There is no processing applied to the content after it is
+   * appended.
+   */
+  virtual void AppendAsTraceFormat(std::string* out) const = 0;
+};
 
 /**
  * V8 Platform abstraction layer.
@@ -54,7 +70,7 @@ class Platform {
     kLongRunningTask
   };
 
-  virtual ~Platform() {}
+  virtual ~Platform() = default;
 
   /**
    * Gets the number of threads that are used to execute background tasks. Is
@@ -159,11 +175,43 @@ class Platform {
   }
 
   /**
+   * Adds a trace event to the platform tracing system. This function call is
+   * usually the result of a TRACE_* macro from trace_event_common.h when
+   * tracing and the category of the particular trace are enabled. It is not
+   * advisable to call this function on its own; it is really only meant to be
+   * used by the trace macros. The returned handle can be used by
+   * UpdateTraceEventDuration to update the duration of COMPLETE events.
+   */
+  virtual uint64_t AddTraceEvent(
+      char phase, const uint8_t* category_enabled_flag, const char* name,
+      const char* scope, uint64_t id, uint64_t bind_id, int32_t num_args,
+      const char** arg_names, const uint8_t* arg_types,
+      const uint64_t* arg_values,
+      std::unique_ptr<ConvertableToTraceFormat>* arg_convertables,
+      unsigned int flags) {
+    return AddTraceEvent(phase, category_enabled_flag, name, scope, id, bind_id,
+                         num_args, arg_names, arg_types, arg_values, flags);
+  }
+
+  /**
    * Sets the duration field of a COMPLETE trace event. It must be called with
    * the handle returned from AddTraceEvent().
    **/
   virtual void UpdateTraceEventDuration(const uint8_t* category_enabled_flag,
                                         const char* name, uint64_t handle) {}
+
+  class TraceStateObserver {
+   public:
+    virtual ~TraceStateObserver() = default;
+    virtual void OnTraceEnabled() = 0;
+    virtual void OnTraceDisabled() = 0;
+  };
+
+  /** Adds tracing state change observer. */
+  virtual void AddTraceStateObserver(TraceStateObserver*) {}
+
+  /** Removes tracing state change observer. */
+  virtual void RemoveTraceStateObserver(TraceStateObserver*) {}
 };
 
 }  // namespace v8
diff --git a/deps/v8/include/v8-profiler.h b/deps/v8/include/v8-profiler.h
index bcb69f3763..6ee0340f3c 100644
--- a/deps/v8/include/v8-profiler.h
+++ b/deps/v8/include/v8-profiler.h
@@ -46,6 +46,20 @@ template class V8_EXPORT std::vector<v8::CpuProfileDeoptInfo>;
 
 namespace v8 {
 
+/**
+ * TracingCpuProfiler monitors tracing being enabled/disabled
+ * and emits CpuProfile trace events once v8.cpu_profile2 tracing category
+ * is enabled. It has no overhead unless the category is enabled.
+ */
+class V8_EXPORT TracingCpuProfiler {
+ public:
+  static std::unique_ptr<TracingCpuProfiler> Create(Isolate*);
+  virtual ~TracingCpuProfiler() = default;
+
+ protected:
+  TracingCpuProfiler() = default;
+};
+
 // TickSample captures the information collected for each sample.
 struct TickSample {
   // Internal profiling (with --prof + tools/$OS-tick-processor) wants to
@@ -131,6 +145,13 @@ class V8_EXPORT CpuProfileNode {
   /** Returns function name (empty string for anonymous functions.) */
   Local<String> GetFunctionName() const;
 
+  /**
+   * Returns function name (empty string for anonymous functions.)
+   * The string ownership is *not* passed to the caller. It stays valid until
+   * profile is deleted. The function is thread safe.
+   */
+  const char* GetFunctionNameStr() const;
+
   /** Returns id of the script where function is located. */
   int GetScriptId() const;
 
@@ -138,6 +159,13 @@ class V8_EXPORT CpuProfileNode {
   Local<String> GetScriptResourceName() const;
 
   /**
+   * Returns resource name for script from where the function originates.
+   * The string ownership is *not* passed to the caller. It stays valid until
+   * profile is deleted. The function is thread safe.
+   */
+  const char* GetScriptResourceNameStr() const;
+
+  /**
    * Returns the number, 1-based, of the line where the function originates.
    * kNoLineNumberInfo if no line number information is available.
    */
diff --git a/deps/v8/include/v8-util.h b/deps/v8/include/v8-util.h
index 8133fdd49d..99c59fe302 100644
--- a/deps/v8/include/v8-util.h
+++ b/deps/v8/include/v8-util.h
@@ -206,14 +206,19 @@ class PersistentValueMapBase {
   }
 
   /**
-   * Call V8::RegisterExternallyReferencedObject with the map value for given
-   * key.
+   * Deprecated. Call V8::RegisterExternallyReferencedObject with the map value
+   * for given key.
+   * TODO(hlopko) Remove once migration to reporter is finished.
    */
-  void RegisterExternallyReferencedObject(K& key) {
+  void RegisterExternallyReferencedObject(K& key) {}
+
+  /**
+   * Use EmbedderReachableReferenceReporter with the map value for given key.
+   */
+  void RegisterExternallyReferencedObject(
+      EmbedderReachableReferenceReporter* reporter, K& key) {
     DCHECK(Contains(key));
-    V8::RegisterExternallyReferencedObject(
-        reinterpret_cast<internal::Object**>(FromVal(Traits::Get(&impl_, key))),
-        reinterpret_cast<internal::Isolate*>(GetIsolate()));
+    reporter->ReportExternalReference(FromVal(Traits::Get(&impl_, key)));
   }
 
   /**
diff --git a/deps/v8/include/v8-version.h b/deps/v8/include/v8-version.h
index a39676e377..b216cf04c3 100644
--- a/deps/v8/include/v8-version.h
+++ b/deps/v8/include/v8-version.h
@@ -9,9 +9,9 @@
 // NOTE these macros are used by some of the tool scripts and the build
 // system so their names cannot be changed without changing the scripts.
 #define V8_MAJOR_VERSION 5
-#define V8_MINOR_VERSION 4
-#define V8_BUILD_NUMBER 500
-#define V8_PATCH_LEVEL 46
+#define V8_MINOR_VERSION 5
+#define V8_BUILD_NUMBER 372
+#define V8_PATCH_LEVEL 40
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)
diff --git a/deps/v8/include/v8.h b/deps/v8/include/v8.h
index d7e39adbae..36edf5334a 100644
--- a/deps/v8/include/v8.h
+++ b/deps/v8/include/v8.h
@@ -51,7 +51,7 @@
 #else  // V8_OS_WIN
 
 // Setup for Linux shared library export.
-#if V8_HAS_ATTRIBUTE_VISIBILITY && defined(V8_SHARED)
+#if V8_HAS_ATTRIBUTE_VISIBILITY
 # ifdef BUILDING_V8_SHARED
 #  define V8_EXPORT __attribute__ ((visibility("default")))
 # else
@@ -70,6 +70,7 @@ namespace v8 {
 
 class AccessorSignature;
 class Array;
+class ArrayBuffer;
 class Boolean;
 class BooleanObject;
 class Context;
@@ -95,6 +96,7 @@ class ObjectTemplate;
 class Platform;
 class Primitive;
 class Promise;
+class PropertyDescriptor;
 class Proxy;
 class RawOperationDescriptor;
 class Script;
@@ -341,7 +343,7 @@ class Local {
 
 
 #if !defined(V8_IMMINENT_DEPRECATION_WARNINGS)
-// Local is an alias for Local for historical reasons.
+// Handle is an alias for Local for historical reasons.
 template <class T>
 using Handle = Local<T>;
 #endif
@@ -466,6 +468,16 @@ class WeakCallbackInfo {
 enum class WeakCallbackType { kParameter, kInternalFields, kFinalizer };
 
 /**
+ * A reporter class that embedder will use to report reachable references found
+ * by EmbedderHeapTracer.
+ */
+class V8_EXPORT EmbedderReachableReferenceReporter {
+ public:
+  virtual void ReportExternalReference(Value* object) = 0;
+  virtual ~EmbedderReachableReferenceReporter() = default;
+};
+
+/**
  * An object reference that is independent of any handle scope.  Where
  * a Local handle only lives as long as the HandleScope in which it was
  * allocated, a PersistentBase handle remains valid until it is explicitly
@@ -562,11 +574,18 @@ template <class T> class PersistentBase {
   V8_INLINE void ClearWeak() { ClearWeak<void>(); }
 
   /**
+   * Deprecated.
+   * TODO(hlopko): remove once migration to reporter is finished.
+   */
+  V8_INLINE void RegisterExternalReference(Isolate* isolate) const {}
+
+  /**
    * Allows the embedder to tell the v8 garbage collector that a certain object
    * is alive. Only allowed when the embedder is asked to trace its heap by
    * EmbedderHeapTracer.
    */
-  V8_INLINE void RegisterExternalReference(Isolate* isolate) const;
+  V8_INLINE void RegisterExternalReference(
+      EmbedderReachableReferenceReporter* reporter) const;
 
   /**
    * Marks the reference to this object independent. Garbage collector is free
@@ -615,6 +634,9 @@ template <class T> class PersistentBase {
    */
   V8_INLINE uint16_t WrapperClassId() const;
 
+  PersistentBase(const PersistentBase& other) = delete;  // NOLINT
+  void operator=(const PersistentBase&) = delete;
+
  private:
   friend class Isolate;
   friend class Utils;
@@ -630,8 +652,6 @@ template <class T> class PersistentBase {
   friend class Object;
 
   explicit V8_INLINE PersistentBase(T* val) : val_(val) {}
-  PersistentBase(const PersistentBase& other) = delete;  // NOLINT
-  void operator=(const PersistentBase&) = delete;
   V8_INLINE static T* New(Isolate* isolate, T* that);
 
   T* val_;
@@ -835,11 +855,12 @@ class Global : public PersistentBase<T> {
    */
   typedef void MoveOnlyTypeForCPP03;
 
+  Global(const Global&) = delete;
+  void operator=(const Global&) = delete;
+
  private:
   template <class F>
   friend class ReturnValue;
-  Global(const Global&) = delete;
-  void operator=(const Global&) = delete;
   V8_INLINE T* operator*() const { return this->val_; }
 };
 
@@ -878,6 +899,11 @@ class V8_EXPORT HandleScope {
     return reinterpret_cast<Isolate*>(isolate_);
   }
 
+  HandleScope(const HandleScope&) = delete;
+  void operator=(const HandleScope&) = delete;
+  void* operator new(size_t size) = delete;
+  void operator delete(void*, size_t) = delete;
+
  protected:
   V8_INLINE HandleScope() {}
 
@@ -891,13 +917,6 @@ class V8_EXPORT HandleScope {
   static internal::Object** CreateHandle(internal::HeapObject* heap_object,
                                          internal::Object* value);
 
-  // Make it hard to create heap-allocated or illegal handle scopes by
-  // disallowing certain operations.
-  HandleScope(const HandleScope&);
-  void operator=(const HandleScope&);
-  void* operator new(size_t size);
-  void operator delete(void*, size_t);
-
   internal::Isolate* isolate_;
   internal::Object** prev_next_;
   internal::Object** prev_limit_;
@@ -932,16 +951,13 @@ class V8_EXPORT EscapableHandleScope : public HandleScope {
     return Local<T>(reinterpret_cast<T*>(slot));
   }
 
+  EscapableHandleScope(const EscapableHandleScope&) = delete;
+  void operator=(const EscapableHandleScope&) = delete;
+  void* operator new(size_t size) = delete;
+  void operator delete(void*, size_t) = delete;
+
  private:
   internal::Object** Escape(internal::Object** escape_value);
-
-  // Make it hard to create heap-allocated or illegal handle scopes by
-  // disallowing certain operations.
-  EscapableHandleScope(const EscapableHandleScope&);
-  void operator=(const EscapableHandleScope&);
-  void* operator new(size_t size);
-  void operator delete(void*, size_t);
-
   internal::Object** escape_slot_;
 };
 
@@ -950,14 +966,12 @@ class V8_EXPORT SealHandleScope {
   SealHandleScope(Isolate* isolate);
   ~SealHandleScope();
 
- private:
-  // Make it hard to create heap-allocated or illegal handle scopes by
-  // disallowing certain operations.
-  SealHandleScope(const SealHandleScope&);
-  void operator=(const SealHandleScope&);
-  void* operator new(size_t size);
-  void operator delete(void*, size_t);
+  SealHandleScope(const SealHandleScope&) = delete;
+  void operator=(const SealHandleScope&) = delete;
+  void* operator new(size_t size) = delete;
+  void operator delete(void*, size_t) = delete;
 
+ private:
   internal::Isolate* const isolate_;
   internal::Object** prev_limit_;
   int prev_sealed_level_;
@@ -1073,6 +1087,47 @@ class V8_EXPORT UnboundScript {
   static const int kNoScriptId = 0;
 };
 
+/**
+ * This is an unfinished experimental feature, and is only exposed
+ * here for internal testing purposes. DO NOT USE.
+ *
+ * A compiled JavaScript module.
+ */
+class V8_EXPORT Module {
+ public:
+  /**
+   * Returns the number of modules requested by this module.
+   */
+  int GetModuleRequestsLength() const;
+
+  /**
+   * Returns the ith module specifier in this module.
+   * i must be < GetModuleRequestsLength() and >= 0.
+   */
+  Local<String> GetModuleRequest(int i) const;
+
+  void SetEmbedderData(Local<Value> data);
+  Local<Value> GetEmbedderData() const;
+
+  typedef MaybeLocal<Module> (*ResolveCallback)(Local<Context> context,
+                                                Local<String> specifier,
+                                                Local<Module> referrer,
+                                                Local<Value> data);
+
+  /**
+   * ModuleDeclarationInstantiation
+   *
+   * Returns false if an exception occurred during instantiation.
+   */
+  V8_WARN_UNUSED_RESULT bool Instantiate(
+      Local<Context> context, ResolveCallback callback,
+      Local<Value> callback_data = Local<Value>());
+
+  /**
+   * ModuleEvaluation
+   */
+  V8_WARN_UNUSED_RESULT MaybeLocal<Value> Evaluate(Local<Context> context);
+};
 
 /**
  * A compiled JavaScript script, tied to a Context which was active when the
@@ -1148,10 +1203,9 @@ class V8_EXPORT ScriptCompiler {
     bool rejected;
     BufferPolicy buffer_policy;
 
-   private:
-    // Prevent copying. Not implemented.
-    CachedData(const CachedData&);
-    CachedData& operator=(const CachedData&);
+    // Prevent copying.
+    CachedData(const CachedData&) = delete;
+    CachedData& operator=(const CachedData&) = delete;
   };
 
   /**
@@ -1171,11 +1225,12 @@ class V8_EXPORT ScriptCompiler {
     // alive.
     V8_INLINE const CachedData* GetCachedData() const;
 
+    // Prevent copying.
+    Source(const Source&) = delete;
+    Source& operator=(const Source&) = delete;
+
    private:
     friend class ScriptCompiler;
-    // Prevent copying. Not implemented.
-    Source(const Source&);
-    Source& operator=(const Source&);
 
     Local<String> source_string;
 
@@ -1258,11 +1313,11 @@ class V8_EXPORT ScriptCompiler {
 
     internal::StreamedSource* impl() const { return impl_; }
 
-   private:
-    // Prevent copying. Not implemented.
-    StreamedSource(const StreamedSource&);
-    StreamedSource& operator=(const StreamedSource&);
+    // Prevent copying.
+    StreamedSource(const StreamedSource&) = delete;
+    StreamedSource& operator=(const StreamedSource&) = delete;
 
+   private:
     internal::StreamedSource* impl_;
   };
 
@@ -1376,18 +1431,17 @@ class V8_EXPORT ScriptCompiler {
   static uint32_t CachedDataVersionTag();
 
   /**
-   * Compile an ES6 module.
-   *
    * This is an unfinished experimental feature, and is only exposed
-   * here for internal testing purposes.
-   * Only parsing works at the moment. Do not use.
+   * here for internal testing purposes. DO NOT USE.
    *
-   * TODO(adamk): Script is likely the wrong return value for this;
-   * should return some new Module type.
+   * Compile an ES module, returning a Module that encapsulates
+   * the compiled code.
+   *
+   * Corresponds to the ParseModule abstract operation in the
+   * ECMAScript specification.
    */
-  static V8_WARN_UNUSED_RESULT MaybeLocal<Script> CompileModule(
-      Local<Context> context, Source* source,
-      CompileOptions options = kNoCompileOptions);
+  static V8_WARN_UNUSED_RESULT MaybeLocal<Module> CompileModule(
+      Isolate* isolate, Source* source);
 
   /**
    * Compile a function for a given context. This is equivalent to running
@@ -1664,6 +1718,174 @@ class V8_EXPORT JSON {
       Local<String> gap = Local<String>());
 };
 
+/**
+ * Value serialization compatible with the HTML structured clone algorithm.
+ * The format is backward-compatible (i.e. safe to store to disk).
+ *
+ * WARNING: This API is under development, and changes (including incompatible
+ * changes to the API or wire format) may occur without notice until this
+ * warning is removed.
+ */
+class V8_EXPORT ValueSerializer {
+ public:
+  class V8_EXPORT Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    /*
+     * Handles the case where a DataCloneError would be thrown in the structured
+     * clone spec. Other V8 embedders may throw some other appropriate exception
+     * type.
+     */
+    virtual void ThrowDataCloneError(Local<String> message) = 0;
+
+    /*
+     * The embedder overrides this method to write some kind of host object, if
+     * possible. If not, a suitable exception should be thrown and
+     * Nothing<bool>() returned.
+     */
+    virtual Maybe<bool> WriteHostObject(Isolate* isolate, Local<Object> object);
+  };
+
+  explicit ValueSerializer(Isolate* isolate);
+  ValueSerializer(Isolate* isolate, Delegate* delegate);
+  ~ValueSerializer();
+
+  /*
+   * Writes out a header, which includes the format version.
+   */
+  void WriteHeader();
+
+  /*
+   * Serializes a JavaScript value into the buffer.
+   */
+  V8_WARN_UNUSED_RESULT Maybe<bool> WriteValue(Local<Context> context,
+                                               Local<Value> value);
+
+  /*
+   * Returns the stored data. This serializer should not be used once the buffer
+   * is released. The contents are undefined if a previous write has failed.
+   */
+  std::vector<uint8_t> ReleaseBuffer();
+
+  /*
+   * Marks an ArrayBuffer as havings its contents transferred out of band.
+   * Pass the corresponding JSArrayBuffer in the deserializing context to
+   * ValueDeserializer::TransferArrayBuffer.
+   */
+  void TransferArrayBuffer(uint32_t transfer_id,
+                           Local<ArrayBuffer> array_buffer);
+
+  /*
+   * Similar to TransferArrayBuffer, but for SharedArrayBuffer.
+   */
+  void TransferSharedArrayBuffer(uint32_t transfer_id,
+                                 Local<SharedArrayBuffer> shared_array_buffer);
+
+  /*
+   * Write raw data in various common formats to the buffer.
+   * Note that integer types are written in base-128 varint format, not with a
+   * binary copy. For use during an override of Delegate::WriteHostObject.
+   */
+  void WriteUint32(uint32_t value);
+  void WriteUint64(uint64_t value);
+  void WriteDouble(double value);
+  void WriteRawBytes(const void* source, size_t length);
+
+ private:
+  ValueSerializer(const ValueSerializer&) = delete;
+  void operator=(const ValueSerializer&) = delete;
+
+  struct PrivateData;
+  PrivateData* private_;
+};
+
+/**
+ * Deserializes values from data written with ValueSerializer, or a compatible
+ * implementation.
+ *
+ * WARNING: This API is under development, and changes (including incompatible
+ * changes to the API or wire format) may occur without notice until this
+ * warning is removed.
+ */
+class V8_EXPORT ValueDeserializer {
+ public:
+  class V8_EXPORT Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    /*
+     * The embedder overrides this method to read some kind of host object, if
+     * possible. If not, a suitable exception should be thrown and
+     * MaybeLocal<Object>() returned.
+     */
+    virtual MaybeLocal<Object> ReadHostObject(Isolate* isolate);
+  };
+
+  ValueDeserializer(Isolate* isolate, const uint8_t* data, size_t size);
+  ValueDeserializer(Isolate* isolate, const uint8_t* data, size_t size,
+                    Delegate* delegate);
+  ~ValueDeserializer();
+
+  /*
+   * Reads and validates a header (including the format version).
+   * May, for example, reject an invalid or unsupported wire format.
+   */
+  V8_WARN_UNUSED_RESULT Maybe<bool> ReadHeader(Local<Context> context);
+  V8_DEPRECATE_SOON("Use Local<Context> version", Maybe<bool> ReadHeader());
+
+  /*
+   * Deserializes a JavaScript value from the buffer.
+   */
+  V8_WARN_UNUSED_RESULT MaybeLocal<Value> ReadValue(Local<Context> context);
+
+  /*
+   * Accepts the array buffer corresponding to the one passed previously to
+   * ValueSerializer::TransferArrayBuffer.
+   */
+  void TransferArrayBuffer(uint32_t transfer_id,
+                           Local<ArrayBuffer> array_buffer);
+
+  /*
+   * Similar to TransferArrayBuffer, but for SharedArrayBuffer.
+   * transfer_id exists in the same namespace as unshared ArrayBuffer objects.
+   */
+  void TransferSharedArrayBuffer(uint32_t transfer_id,
+                                 Local<SharedArrayBuffer> shared_array_buffer);
+
+  /*
+   * Must be called before ReadHeader to enable support for reading the legacy
+   * wire format (i.e., which predates this being shipped).
+   *
+   * Don't use this unless you need to read data written by previous versions of
+   * blink::ScriptValueSerializer.
+   */
+  void SetSupportsLegacyWireFormat(bool supports_legacy_wire_format);
+
+  /*
+   * Reads the underlying wire format version. Likely mostly to be useful to
+   * legacy code reading old wire format versions. Must be called after
+   * ReadHeader.
+   */
+  uint32_t GetWireFormatVersion() const;
+
+  /*
+   * Reads raw data in various common formats to the buffer.
+   * Note that integer types are read in base-128 varint format, not with a
+   * binary copy. For use during an override of Delegate::ReadHostObject.
+   */
+  V8_WARN_UNUSED_RESULT bool ReadUint32(uint32_t* value);
+  V8_WARN_UNUSED_RESULT bool ReadUint64(uint64_t* value);
+  V8_WARN_UNUSED_RESULT bool ReadDouble(double* value);
+  V8_WARN_UNUSED_RESULT bool ReadRawBytes(size_t length, const void** data);
+
+ private:
+  ValueDeserializer(const ValueDeserializer&) = delete;
+  void operator=(const ValueDeserializer&) = delete;
+
+  struct PrivateData;
+  PrivateData* private_;
+};
 
 /**
  * A map whose keys are referenced weakly. It is similar to JavaScript WeakMap
@@ -1811,6 +2033,11 @@ class V8_EXPORT Value : public Data {
   bool IsRegExp() const;
 
   /**
+   * Returns true if this value is an async function.
+   */
+  bool IsAsyncFunction() const;
+
+  /**
    * Returns true if this value is a Generator function.
    * This is an experimental feature.
    */
@@ -2207,11 +2434,11 @@ class V8_EXPORT String : public Name {
      */
     virtual void Dispose() { delete this; }
 
-   private:
     // Disallow copying and assigning.
-    ExternalStringResourceBase(const ExternalStringResourceBase&);
-    void operator=(const ExternalStringResourceBase&);
+    ExternalStringResourceBase(const ExternalStringResourceBase&) = delete;
+    void operator=(const ExternalStringResourceBase&) = delete;
 
+   private:
     friend class v8::internal::Heap;
   };
 
@@ -2413,13 +2640,14 @@ class V8_EXPORT String : public Name {
     char* operator*() { return str_; }
     const char* operator*() const { return str_; }
     int length() const { return length_; }
+
+    // Disallow copying and assigning.
+    Utf8Value(const Utf8Value&) = delete;
+    void operator=(const Utf8Value&) = delete;
+
    private:
     char* str_;
     int length_;
-
-    // Disallow copying and assigning.
-    Utf8Value(const Utf8Value&);
-    void operator=(const Utf8Value&);
   };
 
   /**
@@ -2435,13 +2663,14 @@ class V8_EXPORT String : public Name {
     uint16_t* operator*() { return str_; }
     const uint16_t* operator*() const { return str_; }
     int length() const { return length_; }
+
+    // Disallow copying and assigning.
+    Value(const Value&) = delete;
+    void operator=(const Value&) = delete;
+
    private:
     uint16_t* str_;
     int length_;
-
-    // Disallow copying and assigning.
-    Value(const Value&);
-    void operator=(const Value&);
   };
 
  private:
@@ -2575,11 +2804,17 @@ class V8_EXPORT Uint32 : public Integer {
   static void CheckCast(v8::Value* obj);
 };
 
-
+/**
+ * PropertyAttribute.
+ */
 enum PropertyAttribute {
-  None       = 0,
-  ReadOnly   = 1 << 0,
-  DontEnum   = 1 << 1,
+  /** None. **/
+  None = 0,
+  /** ReadOnly, i.e., not writable. **/
+  ReadOnly = 1 << 0,
+  /** DontEnum, i.e., not enumerable. **/
+  DontEnum = 1 << 1,
+  /** DontDelete, i.e., not configurable. **/
   DontDelete = 1 << 2
 };
 
@@ -2693,6 +2928,22 @@ class V8_EXPORT Object : public Value {
       Local<Context> context, Local<Name> key, Local<Value> value,
       PropertyAttribute attributes = None);
 
+  // Implements Object.DefineProperty(O, P, Attributes), see Ecma-262 19.1.2.4.
+  //
+  // The defineProperty function is used to add an own property or
+  // update the attributes of an existing own property of an object.
+  //
+  // Both data and accessor descriptors can be used.
+  //
+  // In general, CreateDataProperty is faster, however, does not allow
+  // for specifying attributes or an accessor descriptor.
+  //
+  // The PropertyDescriptor can change when redefining a property.
+  //
+  // Returns true on success.
+  V8_WARN_UNUSED_RESULT Maybe<bool> DefineProperty(
+      Local<Context> context, Local<Name> key, PropertyDescriptor& descriptor);
+
   // Sets an own property on this object bypassing interceptors and
   // overriding accessors or read-only properties.
   //
@@ -2736,6 +2987,21 @@ class V8_EXPORT Object : public Value {
       Local<Context> context, Local<String> key);
 
   V8_DEPRECATE_SOON("Use maybe version", bool Has(Local<Value> key));
+  /**
+   * Object::Has() calls the abstract operation HasProperty(O, P) described
+   * in ECMA-262, 7.3.10. Has() returns
+   * true, if the object has the property, either own or on the prototype chain.
+   * Interceptors, i.e., PropertyQueryCallbacks, are called if present.
+   *
+   * Has() has the same side effects as JavaScript's `variable in object`.
+   * For example, calling Has() on a revoked proxy will throw an exception.
+   *
+   * \note Has() converts the key to a name, which possibly calls back into
+   * JavaScript.
+   *
+   * See also v8::Object::HasOwnProperty() and
+   * v8::Object::HasRealNamedProperty().
+   */
   V8_WARN_UNUSED_RESULT Maybe<bool> Has(Local<Context> context,
                                         Local<Value> key);
 
@@ -2900,12 +3166,31 @@ class V8_EXPORT Object : public Value {
 
   // Testers for local properties.
   V8_DEPRECATED("Use maybe version", bool HasOwnProperty(Local<String> key));
+
+  /**
+   * HasOwnProperty() is like JavaScript's Object.prototype.hasOwnProperty().
+   *
+   * See also v8::Object::Has() and v8::Object::HasRealNamedProperty().
+   */
   V8_WARN_UNUSED_RESULT Maybe<bool> HasOwnProperty(Local<Context> context,
                                                    Local<Name> key);
   V8_WARN_UNUSED_RESULT Maybe<bool> HasOwnProperty(Local<Context> context,
                                                    uint32_t index);
   V8_DEPRECATE_SOON("Use maybe version",
                     bool HasRealNamedProperty(Local<String> key));
+  /**
+   * Use HasRealNamedProperty() if you want to check if an object has an own
+   * property without causing side effects, i.e., without calling interceptors.
+   *
+   * This function is similar to v8::Object::HasOwnProperty(), but it does not
+   * call interceptors.
+   *
+   * \note Consider using non-masking interceptors, i.e., the interceptors are
+   * not called if the receiver has the real named property. See
+   * `v8::PropertyHandlerFlags::kNonMasking`.
+   *
+   * See also v8::Object::Has().
+   */
   V8_WARN_UNUSED_RESULT Maybe<bool> HasRealNamedProperty(Local<Context> context,
                                                          Local<Name> key);
   V8_DEPRECATE_SOON("Use maybe version",
@@ -2988,6 +3273,12 @@ class V8_EXPORT Object : public Value {
    */
   Local<Context> CreationContext();
 
+  /** Same as above, but works for Persistents */
+  V8_INLINE static Local<Context> CreationContext(
+      const PersistentBase<Object>& object) {
+    return object.val_->CreationContext();
+  }
+
   /**
    * Checks whether a callback is set by the
    * ObjectTemplate::SetCallAsFunctionHandler method.
@@ -3236,12 +3527,91 @@ class FunctionCallbackInfo {
 template<typename T>
 class PropertyCallbackInfo {
  public:
+  /**
+   * \return The isolate of the property access.
+   */
   V8_INLINE Isolate* GetIsolate() const;
+
+  /**
+   * \return The data set in the configuration, i.e., in
+   * `NamedPropertyHandlerConfiguration` or
+   * `IndexedPropertyHandlerConfiguration.`
+   */
   V8_INLINE Local<Value> Data() const;
+
+  /**
+   * \return The receiver. In many cases, this is the object on which the
+   * property access was intercepted. When using
+   * `Reflect.Get`, `Function.prototype.call`, or similar functions, it is the
+   * object passed in as receiver or thisArg.
+   *
+   * \code
+   *  void GetterCallback(Local<Name> name,
+   *                      const v8::PropertyCallbackInfo<v8::Value>& info) {
+   *     auto context = info.GetIsolate()->GetCurrentContext();
+   *
+   *     v8::Local<v8::Value> a_this =
+   *         info.This()
+   *             ->GetRealNamedProperty(context, v8_str("a"))
+   *             .ToLocalChecked();
+   *     v8::Local<v8::Value> a_holder =
+   *         info.Holder()
+   *             ->GetRealNamedProperty(context, v8_str("a"))
+   *             .ToLocalChecked();
+   *
+   *    CHECK(v8_str("r")->Equals(context, a_this).FromJust());
+   *    CHECK(v8_str("obj")->Equals(context, a_holder).FromJust());
+   *
+   *    info.GetReturnValue().Set(name);
+   *  }
+   *
+   *  v8::Local<v8::FunctionTemplate> templ =
+   *  v8::FunctionTemplate::New(isolate);
+   *  templ->InstanceTemplate()->SetHandler(
+   *      v8::NamedPropertyHandlerConfiguration(GetterCallback));
+   *  LocalContext env;
+   *  env->Global()
+   *      ->Set(env.local(), v8_str("obj"), templ->GetFunction(env.local())
+   *                                           .ToLocalChecked()
+   *                                           ->NewInstance(env.local())
+   *                                           .ToLocalChecked())
+   *      .FromJust();
+   *
+   *  CompileRun("obj.a = 'obj'; var r = {a: 'r'}; Reflect.get(obj, 'x', r)");
+   * \endcode
+   */
   V8_INLINE Local<Object> This() const;
+
+  /**
+   * \return The object in the prototype chain of the receiver that has the
+   * interceptor. Suppose you have `x` and its prototype is `y`, and `y`
+   * has an interceptor. Then `info.This()` is `x` and `info.Holder()` is `y`.
+   * The Holder() could be a hidden object (the global object, rather
+   * than the global proxy).
+   *
+   * \note For security reasons, do not pass the object back into the runtime.
+   */
   V8_INLINE Local<Object> Holder() const;
+
+  /**
+   * \return The return value of the callback.
+   * Can be changed by calling Set().
+   * \code
+   * info.GetReturnValue().Set(...)
+   * \endcode
+   *
+   */
   V8_INLINE ReturnValue<T> GetReturnValue() const;
+
+  /**
+   * \return True if the intercepted function should throw if an error occurs.
+   * Usually, `true` corresponds to `'use strict'`.
+   *
+   * \note Always `false` when intercepting `Reflect.Set()`
+   * independent of the language mode.
+   */
   V8_INLINE bool ShouldThrowOnError() const;
+
   // This shouldn't be public, but the arm compiler needs it.
   static const int kArgsLength = 7;
 
@@ -3431,6 +3801,78 @@ class V8_EXPORT Promise : public Object {
   static void CheckCast(Value* obj);
 };
 
+/**
+ * An instance of a Property Descriptor, see Ecma-262 6.2.4.
+ *
+ * Properties in a descriptor are present or absent. If you do not set
+ * `enumerable`, `configurable`, and `writable`, they are absent. If `value`,
+ * `get`, or `set` are absent, but you must specify them in the constructor, use
+ * empty handles.
+ *
+ * Accessors `get` and `set` must be callable or undefined if they are present.
+ *
+ * \note Only query properties if they are present, i.e., call `x()` only if
+ * `has_x()` returns true.
+ *
+ * \code
+ * // var desc = {writable: false}
+ * v8::PropertyDescriptor d(Local<Value>()), false);
+ * d.value(); // error, value not set
+ * if (d.has_writable()) {
+ *   d.writable(); // false
+ * }
+ *
+ * // var desc = {value: undefined}
+ * v8::PropertyDescriptor d(v8::Undefined(isolate));
+ *
+ * // var desc = {get: undefined}
+ * v8::PropertyDescriptor d(v8::Undefined(isolate), Local<Value>()));
+ * \endcode
+ */
+class V8_EXPORT PropertyDescriptor {
+ public:
+  // GenericDescriptor
+  PropertyDescriptor();
+
+  // DataDescriptor
+  PropertyDescriptor(Local<Value> value);
+
+  // DataDescriptor with writable property
+  PropertyDescriptor(Local<Value> value, bool writable);
+
+  // AccessorDescriptor
+  PropertyDescriptor(Local<Value> get, Local<Value> set);
+
+  ~PropertyDescriptor();
+
+  Local<Value> value() const;
+  bool has_value() const;
+
+  Local<Value> get() const;
+  bool has_get() const;
+  Local<Value> set() const;
+  bool has_set() const;
+
+  void set_enumerable(bool enumerable);
+  bool enumerable() const;
+  bool has_enumerable() const;
+
+  void set_configurable(bool configurable);
+  bool configurable() const;
+  bool has_configurable() const;
+
+  bool writable() const;
+  bool has_writable() const;
+
+  struct PrivateData;
+  PrivateData* get_private() const { return private_; }
+
+  PropertyDescriptor(const PropertyDescriptor&) = delete;
+  void operator=(const PropertyDescriptor&) = delete;
+
+ private:
+  PrivateData* private_;
+};
 
 /**
  * An instance of the built-in Proxy constructor (ECMA-262, 6th Edition,
@@ -3444,7 +3886,7 @@ class V8_EXPORT Proxy : public Object {
   void Revoke();
 
   /**
-   * Creates a new empty Map.
+   * Creates a new Proxy for the target object.
    */
   static MaybeLocal<Proxy> New(Local<Context> context,
                                Local<Object> local_target,
@@ -4296,36 +4738,115 @@ typedef void (*NamedPropertyEnumeratorCallback)(
 
 // TODO(dcarney): Deprecate and remove previous typedefs, and replace
 // GenericNamedPropertyFooCallback with just NamedPropertyFooCallback.
+
 /**
- * GenericNamedProperty[Getter|Setter] are used as interceptors on object.
- * See ObjectTemplate::SetNamedPropertyHandler.
+ * Interceptor for get requests on an object.
+ *
+ * Use `info.GetReturnValue().Set()` to set the return value of the
+ * intercepted get request.
+ *
+ * \param property The name of the property for which the request was
+ * intercepted.
+ * \param info Information about the intercepted request, such as
+ * isolate, receiver, return value, or whether running in `'use strict`' mode.
+ * See `PropertyCallbackInfo`.
+ *
+ * \code
+ *  void GetterCallback(
+ *    Local<Name> name,
+ *    const v8::PropertyCallbackInfo<v8::Value>& info) {
+ *      info.GetReturnValue().Set(v8_num(42));
+ *  }
+ *
+ *  v8::Local<v8::FunctionTemplate> templ =
+ *      v8::FunctionTemplate::New(isolate);
+ *  templ->InstanceTemplate()->SetHandler(
+ *      v8::NamedPropertyHandlerConfiguration(GetterCallback));
+ *  LocalContext env;
+ *  env->Global()
+ *      ->Set(env.local(), v8_str("obj"), templ->GetFunction(env.local())
+ *                                             .ToLocalChecked()
+ *                                             ->NewInstance(env.local())
+ *                                             .ToLocalChecked())
+ *      .FromJust();
+ *  v8::Local<v8::Value> result = CompileRun("obj.a = 17; obj.a");
+ *  CHECK(v8_num(42)->Equals(env.local(), result).FromJust());
+ * \endcode
+ *
+ * See also `ObjectTemplate::SetHandler`.
  */
 typedef void (*GenericNamedPropertyGetterCallback)(
     Local<Name> property, const PropertyCallbackInfo<Value>& info);
 
-
 /**
- * Returns the value if the setter intercepts the request.
- * Otherwise, returns an empty handle.
+ * Interceptor for set requests on an object.
+ *
+ * Use `info.GetReturnValue()` to indicate whether the request was intercepted
+ * or not. If the setter successfully intercepts the request, i.e., if the
+ * request should not be further executed, call
+ * `info.GetReturnValue().Set(value)`. If the setter
+ * did not intercept the request, i.e., if the request should be handled as
+ * if no interceptor is present, do not not call `Set()`.
+ *
+ * \param property The name of the property for which the request was
+ * intercepted.
+ * \param value The value which the property will have if the request
+ * is not intercepted.
+ * \param info Information about the intercepted request, such as
+ * isolate, receiver, return value, or whether running in `'use strict'` mode.
+ * See `PropertyCallbackInfo`.
+ *
+ * See also
+ * `ObjectTemplate::SetHandler.`
  */
 typedef void (*GenericNamedPropertySetterCallback)(
     Local<Name> property, Local<Value> value,
     const PropertyCallbackInfo<Value>& info);
 
-
 /**
- * Returns a non-empty handle if the interceptor intercepts the request.
- * The result is an integer encoding property attributes (like v8::None,
- * v8::DontEnum, etc.)
+ * Intercepts all requests that query the attributes of the
+ * property, e.g., getOwnPropertyDescriptor(), propertyIsEnumerable(), and
+ * defineProperty().
+ *
+ * Use `info.GetReturnValue().Set(value)` to set the property attributes. The
+ * value is an interger encoding a `v8::PropertyAttribute`.
+ *
+ * \param property The name of the property for which the request was
+ * intercepted.
+ * \param info Information about the intercepted request, such as
+ * isolate, receiver, return value, or whether running in `'use strict'` mode.
+ * See `PropertyCallbackInfo`.
+ *
+ * \note Some functions query the property attributes internally, even though
+ * they do not return the attributes. For example, `hasOwnProperty()` can
+ * trigger this interceptor depending on the state of the object.
+ *
+ * See also
+ * `ObjectTemplate::SetHandler.`
  */
 typedef void (*GenericNamedPropertyQueryCallback)(
     Local<Name> property, const PropertyCallbackInfo<Integer>& info);
 
-
 /**
- * Returns a non-empty handle if the deleter intercepts the request.
- * The return value is true if the property could be deleted and false
- * otherwise.
+ * Interceptor for delete requests on an object.
+ *
+ * Use `info.GetReturnValue()` to indicate whether the request was intercepted
+ * or not. If the deleter successfully intercepts the request, i.e., if the
+ * request should not be further executed, call
+ * `info.GetReturnValue().Set(value)` with a boolean `value`. The `value` is
+ * used as the return value of `delete`.
+ *
+ * \param property The name of the property for which the request was
+ * intercepted.
+ * \param info Information about the intercepted request, such as
+ * isolate, receiver, return value, or whether running in `'use strict'` mode.
+ * See `PropertyCallbackInfo`.
+ *
+ * \note If you need to mimic the behavior of `delete`, i.e., throw in strict
+ * mode instead of returning false, use `info.ShouldThrowOnError()` to determine
+ * if you are in strict mode.
+ *
+ * See also `ObjectTemplate::SetHandler.`
  */
 typedef void (*GenericNamedPropertyDeleterCallback)(
     Local<Name> property, const PropertyCallbackInfo<Boolean>& info);
@@ -4338,52 +4859,99 @@ typedef void (*GenericNamedPropertyDeleterCallback)(
 typedef void (*GenericNamedPropertyEnumeratorCallback)(
     const PropertyCallbackInfo<Array>& info);
 
+/**
+ * Interceptor for defineProperty requests on an object.
+ *
+ * Use `info.GetReturnValue()` to indicate whether the request was intercepted
+ * or not. If the definer successfully intercepts the request, i.e., if the
+ * request should not be further executed, call
+ * `info.GetReturnValue().Set(value)`. If the definer
+ * did not intercept the request, i.e., if the request should be handled as
+ * if no interceptor is present, do not not call `Set()`.
+ *
+ * \param property The name of the property for which the request was
+ * intercepted.
+ * \param desc The property descriptor which is used to define the
+ * property if the request is not intercepted.
+ * \param info Information about the intercepted request, such as
+ * isolate, receiver, return value, or whether running in `'use strict'` mode.
+ * See `PropertyCallbackInfo`.
+ *
+ * See also `ObjectTemplate::SetHandler`.
+ */
+typedef void (*GenericNamedPropertyDefinerCallback)(
+    Local<Name> property, const PropertyDescriptor& desc,
+    const PropertyCallbackInfo<Value>& info);
+
+/**
+ * Interceptor for getOwnPropertyDescriptor requests on an object.
+ *
+ * Use `info.GetReturnValue().Set()` to set the return value of the
+ * intercepted request. The return value must be an object that
+ * can be converted to a PropertyDescriptor, e.g., a `v8::value` returned from
+ * `v8::Object::getOwnPropertyDescriptor`.
+ *
+ * \param property The name of the property for which the request was
+ * intercepted.
+ * \info Information about the intercepted request, such as
+ * isolate, receiver, return value, or whether running in `'use strict'` mode.
+ * See `PropertyCallbackInfo`.
+ *
+ * \note If GetOwnPropertyDescriptor is intercepted, it will
+ * always return true, i.e., indicate that the property was found.
+ *
+ * See also `ObjectTemplate::SetHandler`.
+ */
+typedef void (*GenericNamedPropertyDescriptorCallback)(
+    Local<Name> property, const PropertyCallbackInfo<Value>& info);
 
 /**
- * Returns the value of the property if the getter intercepts the
- * request.  Otherwise, returns an empty handle.
+ * See `v8::GenericNamedPropertyGetterCallback`.
  */
 typedef void (*IndexedPropertyGetterCallback)(
     uint32_t index,
     const PropertyCallbackInfo<Value>& info);
 
-
 /**
- * Returns the value if the setter intercepts the request.
- * Otherwise, returns an empty handle.
+ * See `v8::GenericNamedPropertySetterCallback`.
  */
 typedef void (*IndexedPropertySetterCallback)(
     uint32_t index,
     Local<Value> value,
     const PropertyCallbackInfo<Value>& info);
 
-
 /**
- * Returns a non-empty handle if the interceptor intercepts the request.
- * The result is an integer encoding property attributes.
+ * See `v8::GenericNamedPropertyQueryCallback`.
  */
 typedef void (*IndexedPropertyQueryCallback)(
     uint32_t index,
     const PropertyCallbackInfo<Integer>& info);
 
-
 /**
- * Returns a non-empty handle if the deleter intercepts the request.
- * The return value is true if the property could be deleted and false
- * otherwise.
+ * See `v8::GenericNamedPropertyDeleterCallback`.
  */
 typedef void (*IndexedPropertyDeleterCallback)(
     uint32_t index,
     const PropertyCallbackInfo<Boolean>& info);
 
-
 /**
- * Returns an array containing the indices of the properties the
- * indexed property getter intercepts.
+ * See `v8::GenericNamedPropertyEnumeratorCallback`.
  */
 typedef void (*IndexedPropertyEnumeratorCallback)(
     const PropertyCallbackInfo<Array>& info);
 
+/**
+ * See `v8::GenericNamedPropertyDefinerCallback`.
+ */
+typedef void (*IndexedPropertyDefinerCallback)(
+    uint32_t index, const PropertyDescriptor& desc,
+    const PropertyCallbackInfo<Value>& info);
+
+/**
+ * See `v8::GenericNamedPropertyDescriptorCallback`.
+ */
+typedef void (*IndexedPropertyDescriptorCallback)(
+    uint32_t index, const PropertyCallbackInfo<Value>& info);
 
 /**
  * Access type specification.
@@ -4617,23 +5185,37 @@ class V8_EXPORT FunctionTemplate : public Template {
   friend class ObjectTemplate;
 };
 
-
+/**
+ * Configuration flags for v8::NamedPropertyHandlerConfiguration or
+ * v8::IndexedPropertyHandlerConfiguration.
+ */
 enum class PropertyHandlerFlags {
+  /**
+   * None.
+   */
   kNone = 0,
-  // See ALL_CAN_READ above.
+
+  /**
+   * See ALL_CAN_READ above.
+   */
   kAllCanRead = 1,
-  // Will not call into interceptor for properties on the receiver or prototype
-  // chain.  Currently only valid for named interceptors.
+
+  /** Will not call into interceptor for properties on the receiver or prototype
+   * chain, i.e., only call into interceptor for properties that do not exist.
+   * Currently only valid for named interceptors.
+   */
   kNonMasking = 1 << 1,
-  // Will not call into interceptor for symbol lookup.  Only meaningful for
-  // named interceptors.
+
+  /**
+   * Will not call into interceptor for symbol lookup.  Only meaningful for
+   * named interceptors.
+   */
   kOnlyInterceptStrings = 1 << 2,
 };
 
-
 struct NamedPropertyHandlerConfiguration {
   NamedPropertyHandlerConfiguration(
-      /** Note: getter is required **/
+      /** Note: getter is required */
       GenericNamedPropertyGetterCallback getter = 0,
       GenericNamedPropertySetterCallback setter = 0,
       GenericNamedPropertyQueryCallback query = 0,
@@ -4646,6 +5228,27 @@ struct NamedPropertyHandlerConfiguration {
         query(query),
         deleter(deleter),
         enumerator(enumerator),
+        definer(0),
+        descriptor(0),
+        data(data),
+        flags(flags) {}
+
+  NamedPropertyHandlerConfiguration(
+      GenericNamedPropertyGetterCallback getter,
+      GenericNamedPropertySetterCallback setter,
+      GenericNamedPropertyDescriptorCallback descriptor,
+      GenericNamedPropertyDeleterCallback deleter,
+      GenericNamedPropertyEnumeratorCallback enumerator,
+      GenericNamedPropertyDefinerCallback definer,
+      Local<Value> data = Local<Value>(),
+      PropertyHandlerFlags flags = PropertyHandlerFlags::kNone)
+      : getter(getter),
+        setter(setter),
+        query(0),
+        deleter(deleter),
+        enumerator(enumerator),
+        definer(definer),
+        descriptor(descriptor),
         data(data),
         flags(flags) {}
 
@@ -4654,6 +5257,8 @@ struct NamedPropertyHandlerConfiguration {
   GenericNamedPropertyQueryCallback query;
   GenericNamedPropertyDeleterCallback deleter;
   GenericNamedPropertyEnumeratorCallback enumerator;
+  GenericNamedPropertyDefinerCallback definer;
+  GenericNamedPropertyDescriptorCallback descriptor;
   Local<Value> data;
   PropertyHandlerFlags flags;
 };
@@ -4661,7 +5266,7 @@ struct NamedPropertyHandlerConfiguration {
 
 struct IndexedPropertyHandlerConfiguration {
   IndexedPropertyHandlerConfiguration(
-      /** Note: getter is required **/
+      /** Note: getter is required */
       IndexedPropertyGetterCallback getter = 0,
       IndexedPropertySetterCallback setter = 0,
       IndexedPropertyQueryCallback query = 0,
@@ -4674,6 +5279,27 @@ struct IndexedPropertyHandlerConfiguration {
         query(query),
         deleter(deleter),
         enumerator(enumerator),
+        definer(0),
+        descriptor(0),
+        data(data),
+        flags(flags) {}
+
+  IndexedPropertyHandlerConfiguration(
+      IndexedPropertyGetterCallback getter,
+      IndexedPropertySetterCallback setter,
+      IndexedPropertyDescriptorCallback descriptor,
+      IndexedPropertyDeleterCallback deleter,
+      IndexedPropertyEnumeratorCallback enumerator,
+      IndexedPropertyDefinerCallback definer,
+      Local<Value> data = Local<Value>(),
+      PropertyHandlerFlags flags = PropertyHandlerFlags::kNone)
+      : getter(getter),
+        setter(setter),
+        query(0),
+        deleter(deleter),
+        enumerator(enumerator),
+        definer(definer),
+        descriptor(descriptor),
         data(data),
         flags(flags) {}
 
@@ -4682,6 +5308,8 @@ struct IndexedPropertyHandlerConfiguration {
   IndexedPropertyQueryCallback query;
   IndexedPropertyDeleterCallback deleter;
   IndexedPropertyEnumeratorCallback enumerator;
+  IndexedPropertyDefinerCallback definer;
+  IndexedPropertyDescriptorCallback descriptor;
   Local<Value> data;
   PropertyHandlerFlags flags;
 };
@@ -4977,6 +5605,10 @@ class V8_EXPORT Extension {  // NOLINT
   void set_auto_enable(bool value) { auto_enable_ = value; }
   bool auto_enable() { return auto_enable_; }
 
+  // Disallow copying and assigning.
+  Extension(const Extension&) = delete;
+  void operator=(const Extension&) = delete;
+
  private:
   const char* name_;
   size_t source_length_;  // expected to initialize before source_
@@ -4984,10 +5616,6 @@ class V8_EXPORT Extension {  // NOLINT
   int dep_count_;
   const char** deps_;
   bool auto_enable_;
-
-  // Disallow copying and assigning.
-  Extension(const Extension&);
-  void operator=(const Extension&);
 };
 
 
@@ -5213,13 +5841,13 @@ class V8_EXPORT MicrotasksScope {
    */
   static bool IsRunningMicrotasks(Isolate* isolate);
 
+  // Prevent copying.
+  MicrotasksScope(const MicrotasksScope&) = delete;
+  MicrotasksScope& operator=(const MicrotasksScope&) = delete;
+
  private:
   internal::Isolate* const isolate_;
   bool run_;
-
-  // Prevent copying.
-  MicrotasksScope(const MicrotasksScope&);
-  MicrotasksScope& operator=(const MicrotasksScope&);
 };
 
 
@@ -5520,8 +6148,8 @@ enum class MemoryPressureLevel { kNone, kModerate, kCritical };
  * Interface for tracing through the embedder heap. During the v8 garbage
  * collection, v8 collects hidden fields of all potential wrappers, and at the
  * end of its marking phase iterates the collection and asks the embedder to
- * trace through its heap and call PersistentBase::RegisterExternalReference on
- * each js object reachable from any of the given wrappers.
+ * trace through its heap and use reporter to report each js object reachable
+ * from any of the given wrappers.
  *
  * Before the first call to the TraceWrappersFrom function TracePrologue will be
  * called. When the garbage collection cycle is finished, TraceEpilogue will be
@@ -5530,36 +6158,49 @@ enum class MemoryPressureLevel { kNone, kModerate, kCritical };
 class V8_EXPORT EmbedderHeapTracer {
  public:
   enum ForceCompletionAction { FORCE_COMPLETION, DO_NOT_FORCE_COMPLETION };
+
   struct AdvanceTracingActions {
     explicit AdvanceTracingActions(ForceCompletionAction force_completion_)
         : force_completion(force_completion_) {}
 
     ForceCompletionAction force_completion;
   };
+
   /**
-   * V8 will call this method with internal fields of found wrappers.
-   * Embedder is expected to store them in it's marking deque and trace
-   * reachable wrappers from them when asked by AdvanceTracing method.
+   * V8 will call this method with internal fields of found wrappers. The
+   * embedder is expected to store them in its marking deque and trace
+   * reachable wrappers from them when called through |AdvanceTracing|.
    */
   virtual void RegisterV8References(
       const std::vector<std::pair<void*, void*> >& internal_fields) = 0;
+
+  /**
+   * Deprecated.
+   * TODO(hlopko) Remove once the migration to reporter is finished.
+   */
+  virtual void TracePrologue() {}
+
   /**
-   * V8 will call this method at the beginning of the gc cycle.
+   * V8 will call this method at the beginning of a GC cycle. Embedder is
+   * expected to use EmbedderReachableReferenceReporter for reporting all
+   * reachable v8 objects.
    */
-  virtual void TracePrologue() = 0;
+  virtual void TracePrologue(EmbedderReachableReferenceReporter* reporter) {}
+
   /**
    * Embedder is expected to trace its heap starting from wrappers reported by
-   * RegisterV8References method, and call
-   * PersistentBase::RegisterExternalReference() on all reachable wrappers.
+   * RegisterV8References method, and use reporter for all reachable wrappers.
    * Embedder is expected to stop tracing by the given deadline.
    *
    * Returns true if there is still work to do.
    */
   virtual bool AdvanceTracing(double deadline_in_ms,
                               AdvanceTracingActions actions) = 0;
+
   /**
-   * V8 will call this method at the end of the gc cycle. Allocation is *not*
-   * allowed in the TraceEpilogue.
+   * V8 will call this method at the end of a GC cycle.
+   *
+   * Note that allocation is *not* allowed within |TraceEpilogue|.
    */
   virtual void TraceEpilogue() = 0;
 
@@ -5574,6 +6215,11 @@ class V8_EXPORT EmbedderHeapTracer {
    */
   virtual void AbortTracing() {}
 
+  /**
+   * Returns the number of wrappers that are still to be traced by the embedder.
+   */
+  virtual size_t NumberOfWrappersToTrace() { return 0; }
+
  protected:
   virtual ~EmbedderHeapTracer() = default;
 };
@@ -5671,12 +6317,12 @@ class V8_EXPORT Isolate {
 
     ~Scope() { isolate_->Exit(); }
 
+    // Prevent copying of Scope objects.
+    Scope(const Scope&) = delete;
+    Scope& operator=(const Scope&) = delete;
+
    private:
     Isolate* const isolate_;
-
-    // Prevent copying of Scope objects.
-    Scope(const Scope&);
-    Scope& operator=(const Scope&);
   };
 
 
@@ -5690,14 +6336,15 @@ class V8_EXPORT Isolate {
     DisallowJavascriptExecutionScope(Isolate* isolate, OnFailure on_failure);
     ~DisallowJavascriptExecutionScope();
 
+    // Prevent copying of Scope objects.
+    DisallowJavascriptExecutionScope(const DisallowJavascriptExecutionScope&) =
+        delete;
+    DisallowJavascriptExecutionScope& operator=(
+        const DisallowJavascriptExecutionScope&) = delete;
+
    private:
     bool on_failure_;
     void* internal_;
-
-    // Prevent copying of Scope objects.
-    DisallowJavascriptExecutionScope(const DisallowJavascriptExecutionScope&);
-    DisallowJavascriptExecutionScope& operator=(
-        const DisallowJavascriptExecutionScope&);
   };
 
 
@@ -5709,14 +6356,15 @@ class V8_EXPORT Isolate {
     explicit AllowJavascriptExecutionScope(Isolate* isolate);
     ~AllowJavascriptExecutionScope();
 
+    // Prevent copying of Scope objects.
+    AllowJavascriptExecutionScope(const AllowJavascriptExecutionScope&) =
+        delete;
+    AllowJavascriptExecutionScope& operator=(
+        const AllowJavascriptExecutionScope&) = delete;
+
    private:
     void* internal_throws_;
     void* internal_assert_;
-
-    // Prevent copying of Scope objects.
-    AllowJavascriptExecutionScope(const AllowJavascriptExecutionScope&);
-    AllowJavascriptExecutionScope& operator=(
-        const AllowJavascriptExecutionScope&);
   };
 
   /**
@@ -5728,13 +6376,14 @@ class V8_EXPORT Isolate {
     explicit SuppressMicrotaskExecutionScope(Isolate* isolate);
     ~SuppressMicrotaskExecutionScope();
 
-   private:
-    internal::Isolate* const isolate_;
-
     // Prevent copying of Scope objects.
-    SuppressMicrotaskExecutionScope(const SuppressMicrotaskExecutionScope&);
+    SuppressMicrotaskExecutionScope(const SuppressMicrotaskExecutionScope&) =
+        delete;
     SuppressMicrotaskExecutionScope& operator=(
-        const SuppressMicrotaskExecutionScope&);
+        const SuppressMicrotaskExecutionScope&) = delete;
+
+   private:
+    internal::Isolate* const isolate_;
   };
 
   /**
@@ -6460,17 +7109,17 @@ class V8_EXPORT Isolate {
    */
   bool IsInUse();
 
+  Isolate() = delete;
+  ~Isolate() = delete;
+  Isolate(const Isolate&) = delete;
+  Isolate& operator=(const Isolate&) = delete;
+  void* operator new(size_t size) = delete;
+  void operator delete(void*, size_t) = delete;
+
  private:
   template <class K, class V, class Traits>
   friend class PersistentValueMapBase;
 
-  Isolate();
-  Isolate(const Isolate&);
-  ~Isolate();
-  Isolate& operator=(const Isolate&);
-  void* operator new(size_t size);
-  void operator delete(void*, size_t);
-
   void SetObjectGroupId(internal::Object** object, UniqueId id);
   void SetReferenceFromGroup(UniqueId id, internal::Object** object);
   void SetReference(internal::Object** parent, internal::Object** child);
@@ -6857,8 +7506,6 @@ class V8_EXPORT V8 {
                          int* index);
   static Local<Value> GetEternal(Isolate* isolate, int index);
 
-  static void RegisterExternallyReferencedObject(internal::Object** object,
-                                                 internal::Isolate* isolate);
   template <class K, class V, class T>
   friend class PersistentValueMapBase;
 
@@ -6925,12 +7572,12 @@ class SnapshotCreator {
    */
   StartupData CreateBlob(FunctionCodeHandling function_code_handling);
 
+  // Disallow copying and assigning.
+  SnapshotCreator(const SnapshotCreator&) = delete;
+  void operator=(const SnapshotCreator&) = delete;
+
  private:
   void* data_;
-
-  // Disallow copying and assigning.
-  SnapshotCreator(const SnapshotCreator&);
-  void operator=(const SnapshotCreator&);
 };
 
 /**
@@ -7134,15 +7781,14 @@ class V8_EXPORT TryCatch {
     return handler->js_stack_comparable_address_;
   }
 
+  TryCatch(const TryCatch&) = delete;
+  void operator=(const TryCatch&) = delete;
+  void* operator new(size_t size) = delete;
+  void operator delete(void*, size_t) = delete;
+
  private:
   void ResetInternal();
 
-  // Make it hard to create heap-allocated TryCatch blocks.
-  TryCatch(const TryCatch&);
-  void operator=(const TryCatch&);
-  void* operator new(size_t size);
-  void operator delete(void*, size_t);
-
   v8::internal::Isolate* isolate_;
   v8::TryCatch* next_;
   void* exception_;
@@ -7498,16 +8144,16 @@ class V8_EXPORT Locker {
    */
   static bool IsActive();
 
+  // Disallow copying and assigning.
+  Locker(const Locker&) = delete;
+  void operator=(const Locker&) = delete;
+
  private:
   void Initialize(Isolate* isolate);
 
   bool has_lock_;
   bool top_level_;
   internal::Isolate* isolate_;
-
-  // Disallow copying and assigning.
-  Locker(const Locker&);
-  void operator=(const Locker&);
 };
 
 
@@ -7643,8 +8289,8 @@ class Internals {
   static const int kNodeIsPartiallyDependentShift = 4;
   static const int kNodeIsActiveShift = 4;
 
-  static const int kJSObjectType = 0xb7;
-  static const int kJSApiObjectType = 0xb6;
+  static const int kJSObjectType = 0xb9;
+  static const int kJSApiObjectType = 0xb8;
   static const int kFirstNonstringType = 0x80;
   static const int kOddballType = 0x83;
   static const int kForeignType = 0x87;
@@ -7920,11 +8566,10 @@ P* PersistentBase<T>::ClearWeak() {
 }
 
 template <class T>
-void PersistentBase<T>::RegisterExternalReference(Isolate* isolate) const {
+void PersistentBase<T>::RegisterExternalReference(
+    EmbedderReachableReferenceReporter* reporter) const {
   if (IsEmpty()) return;
-  V8::RegisterExternallyReferencedObject(
-      reinterpret_cast<internal::Object**>(this->val_),
-      reinterpret_cast<internal::Isolate*>(isolate));
+  reporter->ReportExternalReference(this->val_);
 }
 
 template <class T>