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..682cb160599eca24f9c9bc77096ec3e50b89bae1 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;
@@ -309,6 +309,8 @@ class CORE_EXPORT HTMLMediaElement : public HTMLElement,
   }
   void setRemotePlaybackClient(WebRemotePlaybackClient*);
 
+  float videoViewportRatio() const { return m_viewportRatio; }
+
  protected:
   HTMLMediaElement(const QualifiedName&, Document&);
   ~HTMLMediaElement() override;
@@ -534,7 +536,7 @@ class CORE_EXPORT HTMLMediaElement : public HTMLElement,
 
   EnumerationHistogram& showControlsHistogram() const;
 
-  void onVisibilityChangedForAutoplay(bool isVisible);
+  void onVideoViewportRatioChanged(float ratio);
 
   UnthrottledThreadTimer<HTMLMediaElement> m_loadTimer;
   UnthrottledThreadTimer<HTMLMediaElement> m_progressEventTimer;
@@ -658,6 +660,8 @@ class CORE_EXPORT HTMLMediaElement : public HTMLElement,
   GC_PLUGIN_IGNORE("http://crbug.com/404577")
   WeakMember<AudioSourceProviderClient> m_audioSourceNode;
 
+  float m_viewportRatio = 0;
+
   // AudioClientImpl wraps an AudioSourceProviderClient.
   // When the audio format is known, Chromium calls setFormat().
   class AudioClientImpl final
@@ -716,11 +720,11 @@ 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;
 };