Adding UseCounter specific for extensions

third_party/WebKit/Source/core/frame/UseCounter.cpp

 /*
  * Copyright (C) 2012 Google, Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1157 matching lines @@
   // Note that SVGImage cases always have an about:blank URL
   if (m_context == DefaultContext &&
       !SchemeRegistry::shouldTrackUsageMetricsForScheme(url.protocol())) {
     m_disableReporting = true;
   }
 
   m_featuresRecorded.clearAll();
   m_CSSRecorded.clearAll();
   m_animatedCSSRecorded.clearAll();
   if (!m_disableReporting && !m_muteCount) {
-    featuresHistogram().count(PageVisits);
+    if (url.protocolIs("chrome-extension"))

[Rick Byers, 2017/04/07 17:46:54]

I think m_disableReporting will still be true in this case, right?

+      extensionFeaturesHistogram().count(PageVisits);
+    else
+      featuresHistogram().count(PageVisits);
     cssHistogram().count(totalPagesMeasuredCSSSampleId());
     animatedCSSHistogram().count(totalPagesMeasuredCSSSampleId());
   }
 }
 
 void UseCounter::count(const Frame* frame, Feature feature) {
   if (!frame)
     return;
   Page* page = frame->page();
   if (!page)
@@ skipping 138 matching lines @@
   DEFINE_STATIC_LOCAL(
       blink::EnumerationHistogram, histogram,
       ("Blink.UseCounter.Features", blink::UseCounter::NumberOfFeatures));
   DEFINE_STATIC_LOCAL(blink::EnumerationHistogram, svgHistogram,
                       ("Blink.UseCounter.SVGImage.Features",
                        blink::UseCounter::NumberOfFeatures));
 
   return m_context == SVGImageContext ? svgHistogram : histogram;
 }
 
+EnumerationHistogram& UseCounter::extensionFeaturesHistogram() const {
+  DEFINE_STATIC_LOCAL(blink::EnumerationHistogram, histogram,
+                      ("Blink.UseCounter.Extensions.Features",
+                       blink::UseCounter::NumberOfFeatures));
+  return histogram;
+}
+
 EnumerationHistogram& UseCounter::cssHistogram() const {
   DEFINE_STATIC_LOCAL(blink::EnumerationHistogram, histogram,
                       ("Blink.UseCounter.CSSProperties", kMaximumCSSSampleId));
   DEFINE_STATIC_LOCAL(
       blink::EnumerationHistogram, svgHistogram,
       ("Blink.UseCounter.SVGImage.CSSProperties", kMaximumCSSSampleId));
 
   return m_context == SVGImageContext ? svgHistogram : histogram;
 }
 
@@ skipping 66 matching lines @@
     }
   }
 
   if (needsPagesMeasuredUpdate)
     cssPropertiesHistogram.count(totalPagesMeasuredCSSSampleId());
 
   m_CSSBits.clearAll();
 }
 
 }  // namespace blink