Monitor the intersection of video and viewport.

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

Index: third_party/WebKit/Source/core/html/HTMLMediaElement.h
diff --git a/third_party/WebKit/Source/core/html/HTMLMediaElement.h b/third_party/WebKit/Source/core/html/HTMLMediaElement.h
index c927eeb9db8409a3900dd725e0749b70eb442480..9af76dc0e49d6019f5b7afe2ff227caef4cc6935 100644
--- a/third_party/WebKit/Source/core/html/HTMLMediaElement.h
+++ b/third_party/WebKit/Source/core/html/HTMLMediaElement.h
@@ -52,7 +52,7 @@ class AudioTrackList;
 class AutoplayUmaHelper;
 class ContentType;
 class CueTimeline;
-class ElementVisibilityObserver;
+class ElementViewportRatioObserver;
 class EnumerationHistogram;
 class Event;
 class ExceptionState;
@@ -534,7 +534,7 @@ class CORE_EXPORT HTMLMediaElement : public HTMLElement,
 
   EnumerationHistogram& showControlsHistogram() const;
 
-  void onVisibilityChangedForAutoplay(bool isVisible);
+  void onVideoViewportRatioChanged(bool isVisible);

[miu, 2016/11/09 22:02:08]

Per comments in other file, this callback method should take the float "ratio"
argument.

[xjz, 2016/11/11 01:07:29]

Done.

 
   UnthrottledThreadTimer<HTMLMediaElement> m_loadTimer;
   UnthrottledThreadTimer<HTMLMediaElement> m_progressEventTimer;
@@ -716,11 +716,11 @@ class CORE_EXPORT HTMLMediaElement : public HTMLElement,
   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<ElementViewportRatioObserver> m_videoViewportRatioObserver;
 
   static URLRegistry* s_mediaStreamRegistry;
 };