1 files changed, 112 insertions, 0 deletions
diff --git a/chromium/chrome/common/prerender_util.cc b/chromium/chrome/common/prerender_util.cc
new file mode 100644
index 00000000000..70282cf5107
--- /dev/null
+++ b/chromium/chrome/common/prerender_util.cc
@@ -0,0 +1,112 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/common/prerender_util.h"
+
+#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_functions.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+#include "extensions/common/constants.h"
+#include "url/gurl.h"
+#include "url/url_constants.h"
+
+namespace prerender {
+
+namespace {
+
+// Valid HTTP methods for both prefetch and prerendering.
+const char* const kValidHttpMethods[] = {
+    "GET", "HEAD",
+};
+
+// Additional valid HTTP methods for prerendering.
+const char* const kValidHttpMethodsForPrerendering[] = {
+    "OPTIONS", "POST", "TRACE",
+};
+
+// This enum is used to define the buckets for the
+// "Prerender.NoStatePrefetchResourceCount" histogram family.
+// Hence, existing enumerated constants should never be deleted or reordered,
+// and new constants should only be appended at the end of the enumeration.
+enum NoStatePrefetchResponseType {
+  NO_STORE = 1 << 0,
+  REDIRECT = 1 << 1,
+  MAIN_RESOURCE = 1 << 2,
+  NO_STATE_PREFETCH_RESPONSE_TYPE_COUNT = 1 << 3
+};
+
+int GetResourceType(bool is_main_resource, bool is_redirect, bool is_no_store) {
+  return (is_no_store * NO_STORE) + (is_redirect * REDIRECT) +
+         (is_main_resource * MAIN_RESOURCE);
+}
+
+}  // namespace
+
+const char kFollowOnlyWhenPrerenderShown[] = "follow-only-when-prerender-shown";
+
+bool DoesURLHaveValidScheme(const GURL& url) {
+  return (url.SchemeIsHTTPOrHTTPS() ||
+          url.SchemeIs(extensions::kExtensionScheme) ||
+          url.SchemeIs(url::kDataScheme));
+}
+
+bool DoesSubresourceURLHaveValidScheme(const GURL& url) {
+  return DoesURLHaveValidScheme(url) || url == url::kAboutBlankURL;
+}
+
+bool IsValidHttpMethod(PrerenderMode prerender_mode,
+                       const std::string& method) {
+  DCHECK_NE(prerender_mode, NO_PRERENDER);
+  // |method| has been canonicalized to upper case at this point so we can just
+  // compare them.
+  DCHECK_EQ(method, base::ToUpperASCII(method));
+  for (auto* valid_method : kValidHttpMethods) {
+    if (method == valid_method)
+      return true;
+  }
+
+  if (prerender_mode == PREFETCH_ONLY)
+    return false;
+
+  for (auto* valid_method : kValidHttpMethodsForPrerendering) {
+    if (method == valid_method)
+      return true;
+  }
+
+  return false;
+}
+
+std::string ComposeHistogramName(const std::string& prefix_type,
+                                 const std::string& name) {
+  if (prefix_type.empty())
+    return std::string("Prerender.") + name;
+  return std::string("Prerender.") + prefix_type + std::string("_") + name;
+}
+
+void RecordPrefetchResponseReceived(const std::string& histogram_prefix,
+                                    bool is_main_resource,
+                                    bool is_redirect,
+                                    bool is_no_store) {
+  int sample = GetResourceType(is_main_resource, is_redirect, is_no_store);
+  std::string histogram_name =
+      ComposeHistogramName(histogram_prefix, "NoStatePrefetchResponseTypes");
+  base::UmaHistogramExactLinear(histogram_name, sample,
+                                NO_STATE_PREFETCH_RESPONSE_TYPE_COUNT);
+}
+
+void RecordPrefetchRedirectCount(const std::string& histogram_prefix,
+                                 bool is_main_resource,
+                                 int redirect_count) {
+  const int kMaxRedirectCount = 10;
+  std::string histogram_base_name = base::StringPrintf(
+      "NoStatePrefetch%sResourceRedirects", is_main_resource ? "Main" : "Sub");
+  std::string histogram_name =
+      ComposeHistogramName(histogram_prefix, histogram_base_name);
+  base::UmaHistogramExactLinear(histogram_name, redirect_count,
+                                kMaxRedirectCount);
+}
+
+}  // namespace prerender