Monitor the intersection of video and viewport.

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
@@ skipping 34 matching lines @@
 #include <memory>
 
 namespace blink {
 
 class AudioSourceProviderClient;
 class AudioTrack;
 class AudioTrackList;
 class AutoplayUmaHelper;
 class ContentType;
 class CueTimeline;
-class ElementVisibilityObserver;
+class ViewportIntersectionObserver;
 class EnumerationHistogram;
 class Event;
 class ExceptionState;
 class HTMLSourceElement;
 class HTMLTrackElement;
 class KURL;
 class MediaControls;
 class MediaError;
 class MediaStreamDescriptor;
 class HTMLMediaSource;
@@ skipping 236 matching lines @@
 
   // Temporary callback for crbug.com/487345,402044
   void notifyPositionMayHaveChanged(const IntRect&);
   void updatePositionNotificationRegistration();
 
   WebRemotePlaybackClient* remotePlaybackClient() {
     return m_remotePlaybackClient;
   }
   void setRemotePlaybackClient(WebRemotePlaybackClient*);
 
+  WebMediaPlayer::ViewportIntersectionInfo viewportIntersectInfo() const {

[miu, 2016/11/16 02:40:26]

naming suggestion: How about something more descriptive like
currentViewportIntersection() and |m_currentViewportIntersection|?

[xjz, 2016/11/16 07:45:55]

Done.

+    return m_viewportIntersectInfo;
+  }
+
  protected:
   HTMLMediaElement(const QualifiedName&, Document&);
   ~HTMLMediaElement() override;
   void dispose();
 
   void parseAttribute(const QualifiedName&,
                       const AtomicString&,
                       const AtomicString&) override;
   void finishParsingChildren() final;
   bool isURLAttribute(const Attribute&) const override;
@@ skipping 205 matching lines @@
   void scheduleResolvePlayPromises();
   void scheduleRejectPlayPromises(ExceptionCode);
   void scheduleNotifyPlaying();
   void resolveScheduledPlayPromises();
   void rejectScheduledPlayPromises();
   void rejectPlayPromises(ExceptionCode, const String&);
   void rejectPlayPromisesInternal(ExceptionCode, const String&);
 
   EnumerationHistogram& showControlsHistogram() const;
 
-  void onVisibilityChangedForAutoplay(bool isVisible);
+  void onVideoViewportIntersectionChanged(const WebRect& rootRect,
+                                          const WebRect& intersectRect);
 
   UnthrottledThreadTimer<HTMLMediaElement> m_loadTimer;
   UnthrottledThreadTimer<HTMLMediaElement> m_progressEventTimer;
   UnthrottledThreadTimer<HTMLMediaElement> m_playbackProgressTimer;
   UnthrottledThreadTimer<HTMLMediaElement> m_audioTracksTimer;
   Member<TimeRanges> m_playedTimeRanges;
   Member<GenericEventQueue> m_asyncEventQueue;
 
   double m_playbackRate;
   double m_defaultPlaybackRate;
@@ skipping 103 matching lines @@
   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;
 
+  WebMediaPlayer::ViewportIntersectionInfo m_viewportIntersectInfo;
+
   // 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 38 matching lines @@
 
   friend class AutoplayUmaHelper;  // for isAutoplayAllowedPerSettings
   friend class Internals;
   friend class TrackDisplayUpdateScope;
   friend class AutoplayExperimentHelper;
   friend class MediaControlsTest;
 
   Member<AutoplayExperimentHelper::Client> m_autoplayHelperClient;
   Member<AutoplayExperimentHelper> m_autoplayHelper;
   Member<AutoplayUmaHelper> m_autoplayUmaHelper;
+  bool m_shouldAutoplayWhenVisible = false;
 
   WebRemotePlaybackClient* m_remotePlaybackClient;
 
-  // class AutoplayVisibilityObserver;
-  Member<ElementVisibilityObserver> m_autoplayVisibilityObserver;
+  Member<ViewportIntersectionObserver> m_viewportIntersectionObserver;
 
   static URLRegistry* s_mediaStreamRegistry;
 };
 
 inline bool isHTMLMediaElement(const HTMLElement& element) {
   return isHTMLAudioElement(element) || isHTMLVideoElement(element);
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 }  // namespace blink
 
 #endif  // HTMLMediaElement_h