Monitor the intersection of video and viewport.

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

Index: third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
diff --git a/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h b/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
index 7dda64bb56d55bc2b799c5290a8a9b9f2c420e88..34e43f03d9bf6b5d358de9fdc8bfa65653e6c4b8 100644
--- a/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
+++ b/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
@@ -58,6 +58,8 @@ class AutoplayUmaHelper final : public EventListener {
 
   bool hasSource() const { return m_source != AutoplaySource::NumberOfSources; }
 
+  void visibilityMaybeChangedforMutedVideo(bool isVisible);
+
   DECLARE_VIRTUAL_TRACE();
 
  private:
@@ -77,9 +79,6 @@ class AutoplayUmaHelper final : public EventListener {
   void maybeStartRecordingMutedVideoOffscreenDuration();
   void maybeStopRecordingMutedVideoOffscreenDuration();
 
-  void onVisibilityChangedForMutedVideoOffscreenDuration(bool isVisibile);
-  void onVisibilityChangedForMutedVideoPlayMethodBecomeVisible(bool isVisible);
-
   bool shouldListenToUnloadEvent() const;
 
   // The autoplay source. Use AutoplaySource::NumberOfSources for invalid
@@ -88,10 +87,10 @@ class AutoplayUmaHelper final : public EventListener {
   // The media element this UMA helper is attached to. |m_element| owns |this|.
   Member<HTMLMediaElement> m_element;
 
-  // The observer is used to observe whether a muted video autoplaying by play()
-  // method become visible at some point.
-  // The UMA is pending for recording as long as this observer is non-null.
-  Member<ElementVisibilityObserver> m_mutedVideoPlayMethodVisibilityObserver;
+  // Indicates whether is observing the visibility of a muted video autoplayed
+  // from 'play()' method. The UMA is pending for recording as long as this is
+  // true.
+  bool m_isObservingVisibilityOfMutedAutoplayVideo = false;

[Zhiqiang Zhang (Slow), 2016/11/15 11:29:27]

nit: Currently, this is describing more than what we use it for.
You can rename it `m_isObservingMutedVideoPlayMethodBecomeVisible`, and change
the comment accordingly.

[xjz, 2016/11/15 23:03:39]

Done.

 
   // -----------------------------------------------------------------------
   // Variables used for recording the duration of autoplay muted video playing
@@ -108,11 +107,10 @@ class AutoplayUmaHelper final : public EventListener {
   // Whether an autoplaying muted video is visible.
   bool m_isVisible;
 
-  // The observer is used to observer an autoplaying muted video changing it's
-  // visibility, which is used for offscreen duration UMA.  The UMA is pending
-  // for recording as long as this observer is non-null.
-  Member<ElementVisibilityObserver>
-      m_mutedVideoOffscreenDurationVisibilityObserver;
+  // Indicates whether is observing the visibility of a muted autoplay video for
+  // offscreen duration UMA.  The UMA is pending for recording as long as this
+  // is true.
+  bool m_isObservingVisibilityOfMutedVideoOffscreenDuration = false;
 };
 
 }  // namespace blink