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diff --git a/deps/v8/src/incremental-marking.h b/deps/v8/src/incremental-marking.h
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+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_INCREMENTAL_MARKING_H_
+#define V8_INCREMENTAL_MARKING_H_
+
+
+#include "execution.h"
+#include "mark-compact.h"
+#include "objects.h"
+
+namespace v8 {
+namespace internal {
+
+
+class IncrementalMarking {
+ public:
+  enum State {
+    STOPPED,
+    SWEEPING,
+    MARKING,
+    COMPLETE
+  };
+
+  explicit IncrementalMarking(Heap* heap);
+
+  void TearDown();
+
+  State state() {
+    ASSERT(state_ == STOPPED || FLAG_incremental_marking);
+    return state_;
+  }
+
+  bool should_hurry() { return should_hurry_; }
+
+  inline bool IsStopped() { return state() == STOPPED; }
+
+  inline bool IsMarking() { return state() >= MARKING; }
+
+  inline bool IsMarkingIncomplete() { return state() == MARKING; }
+
+  bool WorthActivating();
+
+  void Start();
+
+  void Stop();
+
+  void PrepareForScavenge();
+
+  void UpdateMarkingDequeAfterScavenge();
+
+  void Hurry();
+
+  void Finalize();
+
+  void Abort();
+
+  void MarkingComplete();
+
+  // It's hard to know how much work the incremental marker should do to make
+  // progress in the face of the mutator creating new work for it.  We start
+  // of at a moderate rate of work and gradually increase the speed of the
+  // incremental marker until it completes.
+  // Do some marking every time this much memory has been allocated.
+  static const intptr_t kAllocatedThreshold = 65536;
+  // Start off by marking this many times more memory than has been allocated.
+  static const intptr_t kInitialAllocationMarkingFactor = 1;
+  // But if we are promoting a lot of data we need to mark faster to keep up
+  // with the data that is entering the old space through promotion.
+  static const intptr_t kFastMarking = 3;
+  // After this many steps we increase the marking/allocating factor.
+  static const intptr_t kAllocationMarkingFactorSpeedupInterval = 1024;
+  // This is how much we increase the marking/allocating factor by.
+  static const intptr_t kAllocationMarkingFactorSpeedup = 2;
+  static const intptr_t kMaxAllocationMarkingFactor = 1000000000;
+
+  void OldSpaceStep(intptr_t allocated) {
+    Step(allocated * kFastMarking / kInitialAllocationMarkingFactor);
+  }
+  void Step(intptr_t allocated);
+
+  inline void RestartIfNotMarking() {
+    if (state_ == COMPLETE) {
+      state_ = MARKING;
+      if (FLAG_trace_incremental_marking) {
+        PrintF("[IncrementalMarking] Restarting (new grey objects)\n");
+      }
+    }
+  }
+
+  static void RecordWriteFromCode(HeapObject* obj,
+                                  Object* value,
+                                  Isolate* isolate);
+
+  static void RecordWriteForEvacuationFromCode(HeapObject* obj,
+                                               Object** slot,
+                                               Isolate* isolate);
+
+  inline bool BaseRecordWrite(HeapObject* obj, Object** slot, Object* value);
+
+
+  inline void RecordWrite(HeapObject* obj, Object** slot, Object* value);
+  inline void RecordWriteIntoCode(HeapObject* obj,
+                                  RelocInfo* rinfo,
+                                  Object* value);
+  void RecordCodeTargetPatch(Address pc, HeapObject* value);
+  void RecordWriteOfCodeEntry(JSFunction* host, Object** slot, Code* value);
+
+  inline void RecordWrites(HeapObject* obj);
+
+  inline void BlackToGreyAndUnshift(HeapObject* obj, MarkBit mark_bit);
+
+  inline void WhiteToGreyAndPush(HeapObject* obj, MarkBit mark_bit);
+
+  inline void WhiteToGrey(HeapObject* obj, MarkBit mark_bit);
+
+  // Does white->black or keeps gray or black color. Returns true if converting
+  // white to black.
+  inline bool MarkBlackOrKeepGrey(MarkBit mark_bit) {
+    ASSERT(!Marking::IsImpossible(mark_bit));
+    if (mark_bit.Get()) {
+      // Grey or black: Keep the color.
+      return false;
+    }
+    mark_bit.Set();
+    ASSERT(Marking::IsBlack(mark_bit));
+    return true;
+  }
+
+  inline int steps_count() {
+    return steps_count_;
+  }
+
+  inline double steps_took() {
+    return steps_took_;
+  }
+
+  inline double longest_step() {
+    return longest_step_;
+  }
+
+  inline int steps_count_since_last_gc() {
+    return steps_count_since_last_gc_;
+  }
+
+  inline double steps_took_since_last_gc() {
+    return steps_took_since_last_gc_;
+  }
+
+  inline void SetOldSpacePageFlags(MemoryChunk* chunk) {
+    SetOldSpacePageFlags(chunk, IsMarking(), IsCompacting());
+  }
+
+  inline void SetNewSpacePageFlags(NewSpacePage* chunk) {
+    SetNewSpacePageFlags(chunk, IsMarking());
+  }
+
+  MarkingDeque* marking_deque() { return &marking_deque_; }
+
+  bool IsCompacting() { return IsMarking() && is_compacting_; }
+
+  void ActivateGeneratedStub(Code* stub);
+
+  void NotifyOfHighPromotionRate() {
+    if (IsMarking()) {
+      if (allocation_marking_factor_ < kFastMarking) {
+        if (FLAG_trace_gc) {
+          PrintF("Increasing marking speed to %d due to high promotion rate\n",
+                 static_cast<int>(kFastMarking));
+        }
+        allocation_marking_factor_ = kFastMarking;
+      }
+    }
+  }
+
+ private:
+  void set_should_hurry(bool val) {
+    should_hurry_ = val;
+  }
+
+  int64_t SpaceLeftInOldSpace();
+
+  void ResetStepCounters();
+
+  void StartMarking();
+
+  void ActivateIncrementalWriteBarrier(PagedSpace* space);
+  static void ActivateIncrementalWriteBarrier(NewSpace* space);
+  void ActivateIncrementalWriteBarrier();
+
+  static void DeactivateIncrementalWriteBarrierForSpace(PagedSpace* space);
+  static void DeactivateIncrementalWriteBarrierForSpace(NewSpace* space);
+  void DeactivateIncrementalWriteBarrier();
+
+  static void SetOldSpacePageFlags(MemoryChunk* chunk,
+                                   bool is_marking,
+                                   bool is_compacting);
+
+  static void SetNewSpacePageFlags(NewSpacePage* chunk, bool is_marking);
+
+  void EnsureMarkingDequeIsCommitted();
+
+  void VisitGlobalContext(Context* ctx, ObjectVisitor* v);
+
+  Heap* heap_;
+
+  State state_;
+  bool is_compacting_;
+
+  VirtualMemory* marking_deque_memory_;
+  MarkingDeque marking_deque_;
+
+  int steps_count_;
+  double steps_took_;
+  double longest_step_;
+  int64_t old_generation_space_available_at_start_of_incremental_;
+  int64_t old_generation_space_used_at_start_of_incremental_;
+  int steps_count_since_last_gc_;
+  double steps_took_since_last_gc_;
+  int64_t bytes_rescanned_;
+  bool should_hurry_;
+  int allocation_marking_factor_;
+  intptr_t allocated_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_INCREMENTAL_MARKING_H_