Record the offscreen playing duration of autoplaying muted videos

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

 /*
  * 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 475 matching lines @@
     void scheduleRejectPlayPromises(ExceptionCode);
     void scheduleNotifyPlaying();
     void resolveScheduledPlayPromises();
     void rejectScheduledPlayPromises();
     void rejectPlayPromises(ExceptionCode, const String&);
     void rejectPlayPromisesInternal(ExceptionCode, const String&);
 
     EnumerationHistogram& showControlsHistogram() const;
 
     void recordAutoplaySourceMetric(int source);
+    void recordAutoplayVideoOffscreenMetric(double timeDeltaMS);
 
     void onVisibilityChangedForAutoplay(bool isVisible);
 
     UnthrottledTimer<HTMLMediaElement> m_loadTimer;
     UnthrottledTimer<HTMLMediaElement> m_progressEventTimer;
     UnthrottledTimer<HTMLMediaElement> m_playbackProgressTimer;
     UnthrottledTimer<HTMLMediaElement> m_audioTracksTimer;
     Member<TimeRanges> m_playedTimeRanges;
     Member<GenericEventQueue> m_asyncEventQueue;
 
@@ skipping 99 matching lines @@
     std::unique_ptr<CancellableTaskFactory> m_playPromiseRejectTask;
     HeapVector<Member<ScriptPromiseResolver>> m_playPromiseResolveList;
     HeapVector<Member<ScriptPromiseResolver>> m_playPromiseRejectList;
     ExceptionCode m_playPromiseErrorCode;
 
     // This is a weak reference, since m_audioSourceNode holds a reference to us.
     // TODO(Oilpan): Consider making this a strongly traced pointer with oilpan where strong cycles are not a problem.
     GC_PLUGIN_IGNORE("http://crbug.com/404577")
     WeakMember<AudioSourceProviderClient> m_audioSourceNode;
 
+    // Variables used for recording the duration of autoplay muted video playing offscreen.
+    // The variables are valid when |m_autoplayOffscrenVisibilityObserver| is non-null. Whenever the playback pauses, the UMA is recorded, and |m_autoplayOffscreenVisibilityObserver| is set to null.
+    double m_mutedVideoAutoplayStartTimeMS;
+    double m_mutedVideoAutoplayOffscreenDurationMS;
+    bool m_isVisible;
+    bool m_isAutoplayFromAttribute;
+    Member<ElementVisibilityObserver> m_autoplayOffscreenVisibilityObserver;
+
+    void maybeRecordMutedVideoAutoplayOffscreenDuration();
+
+    void onVisibilityChangedForAutoplayOffscreen(bool isVisibile);
+
     // AudioClientImpl wraps an AudioSourceProviderClient.
     // When the audio format is known, Chromium calls setFormat().
     class AudioClientImpl final : public GarbageCollectedFinalized<AudioClientImpl>, public WebAudioSourceProviderClient {
     public:
         explicit AudioClientImpl(AudioSourceProviderClient* client)
             : m_client(client)
         {
         }
 
         ~AudioClientImpl() override { }
@@ skipping 57 matching lines @@
 inline bool isHTMLMediaElement(const HTMLElement& element)
 {
     return isHTMLAudioElement(element) || isHTMLVideoElement(element);
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 } // namespace blink
 
 #endif // HTMLMediaElement_h