[Media, Autoplay] Add UMA to record autoplay source

third_party/WebKit/Source/core/html/HTMLMediaElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple 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 263 matching lines @@
     case WebMediaPlayer::PreloadMetaData:
         return "metadata";
     case WebMediaPlayer::PreloadAuto:
         return "auto";
     }
 
     NOTREACHED();
     return String();
 }
 
+// These values are used for histograms. Do not reorder.
+enum AutoplaySource {
+    // Autoplay comes from HTMLMediaElement `autoplay` attribute.
+    AutoplaySourceAttribute = 0,
+    // Autoplay comes from `play()` method.
+    AutoplaySourceMethod = 1,
+    // This enum value must be last.
+    NumberOfAutoplaySources = 2,
+};
+
 } // anonymous namespace
 
 class HTMLMediaElement::AutoplayHelperClientImpl :
     public AutoplayExperimentHelper::Client {
 
 public:
     static AutoplayHelperClientImpl* create(HTMLMediaElement* element)
     {
         return new AutoplayHelperClientImpl(element);
     }
@@ skipping 1317 matching lines @@
 
     if (m_readyState == HAVE_ENOUGH_DATA && oldState < HAVE_ENOUGH_DATA && tracksAreReady) {
         if (oldState <= HAVE_CURRENT_DATA) {
             scheduleEvent(EventTypeNames::canplay);
             if (isPotentiallyPlaying)
                 scheduleNotifyPlaying();
         }
 
         // Check for autoplay, and record metrics about it if needed.
         if (shouldAutoplay(RecordMetricsBehavior::DoRecord)) {
+            recordAutoplaySourceMetric(AutoplaySourceAttribute);
             // If the autoplay experiment says that it's okay to play now,
             // then don't require a user gesture.
             m_autoplayHelper->becameReadyToPlay();
 
             if (!isGestureNeededForPlayback()) {
                 m_paused = false;
                 invalidateCachedTime();
                 scheduleEvent(EventTypeNames::play);
                 scheduleNotifyPlaying();
                 m_autoplaying = false;
@@ skipping 410 matching lines @@
     ScriptPromise promise = resolver->promise();
 
     m_playResolvers.append(resolver);
     return promise;
 }
 
 Nullable<ExceptionCode> HTMLMediaElement::play()
 {
     DVLOG(MEDIA_LOG_LEVEL) << "play(" << (void*)this << ")";
 
+    recordAutoplaySourceMetric(AutoplaySourceMethod);

[mlamouri (slow - plz ping), 2016/06/08 12:30:03]

What we call "autoplay" is when there is no user gesture associated with the
play() method so I think this should be inside the "if
(!UserGestureIndicator::processingUserGesture())" block.

[Zhiqiang Zhang (Slow), 2016/06/08 12:55:14]

Done.

     m_autoplayHelper->playMethodCalled();
 
     if (!UserGestureIndicator::processingUserGesture()) {
         if (isGestureNeededForPlayback()) {
             // If playback is deferred, then don't start playback but don't
             // fail yet either.
             if (m_autoplayHelper->isPlaybackDeferred())
                 return nullptr;
 
             // If we're already playing, then this play would do nothing anyway.
@@ skipping 1703 matching lines @@
 {
     if (isHTMLVideoElement()) {
         DEFINE_STATIC_LOCAL(EnumerationHistogram, histogram, ("Media.Controls.Show.Video", MediaControlsShowMax));
         return histogram;
     }
 
     DEFINE_STATIC_LOCAL(EnumerationHistogram, histogram, ("Media.Controls.Show.Audio", MediaControlsShowMax));
     return histogram;
 }
 
+void HTMLMediaElement::recordAutoplaySourceMetric(int source)
+{
+    DEFINE_STATIC_LOCAL(EnumerationHistogram, videoHistogram, ("Blink.MediaElement.Autoplay.Source.Video", NumberOfAutoplaySources));
+    DEFINE_STATIC_LOCAL(EnumerationHistogram, mutedVideoHistogram, ("Blink.MediaElement.Autoplay.Source.Video.Muted", NumberOfAutoplaySources));
+    DEFINE_STATIC_LOCAL(EnumerationHistogram, audioHistogram, ("Blink.MediaElement.Autoplay.Source.Audio", NumberOfAutoplaySources));
+
+    if (isHTMLVideoElement()) {
+        videoHistogram.count(source);
+        if (muted())
+            mutedVideoHistogram.count(source);
+    } else {
+        audioHistogram.count(source);
+    }
+}
+
 void HTMLMediaElement::clearWeakMembers(Visitor* visitor)
 {
     if (!ThreadHeap::isHeapObjectAlive(m_audioSourceNode)) {
         getAudioSourceProvider().setClient(nullptr);
         m_audioSourceNode = nullptr;
     }
 }
 
 void HTMLMediaElement::AudioSourceProviderImpl::wrap(WebAudioSourceProvider* provider)
 {
@@ skipping 97 matching lines @@
 
 IntRect HTMLMediaElement::AutoplayHelperClientImpl::absoluteBoundingBoxRect() const
 {
     IntRect result;
     if (LayoutObject* object = m_element->layoutObject())
         result = object->absoluteBoundingBoxRect();
     return result;
 }
 
 } // namespace blink