Hide overlay play button if it can't be shown without clipping

third_party/WebKit/Source/core/html/shadow/MediaControls.h

Index: third_party/WebKit/Source/core/html/shadow/MediaControls.h
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControls.h b/third_party/WebKit/Source/core/html/shadow/MediaControls.h
index 5ced7c1bb568479c6d9a85fa667a07c99240e780..6698f446d40c3c43c105d6f0c4a88871a48a57b0 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControls.h
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControls.h
@@ -87,9 +87,6 @@ class CORE_EXPORT MediaControls final : public HTMLDivElement {
     return m_volumeSlider;
   }
 
-  // Notify us that our controls enclosure has changed width.
-  void notifyPanelWidthChanged(const LayoutUnit& newWidth);
-
   // Notify us that the media element's network state has changed.
   void networkStateChanged();
 
@@ -130,7 +127,12 @@ class CORE_EXPORT MediaControls final : public HTMLDivElement {
 
   void invalidate(Element*);
 
+  // Need to be members of MediaControls for private member access.
   class BatchedControlUpdate;
+  class MediaControlsResizeObserverCallback;
+
+  // Notify us that our controls enclosure has changed size.
+  void notifyElementSizeChanged(ClientRect* newSize);
 
   explicit MediaControls(HTMLMediaElement&);
 
@@ -155,12 +157,13 @@ class CORE_EXPORT MediaControls final : public HTMLDivElement {
   void stopHideMediaControlsTimer();
   void resetHideMediaControlsTimer();
 
-  void panelWidthChangedTimerFired(TimerBase*);
+  void elementSizeChangedTimerFired(TimerBase*);
 
   void hideAllMenus();
 
   // Hide elements that don't fit, and show those things that we want which
-  // do fit.  This requires that m_panelWidth is current.
+  // do fit.  This requires that m_effectiveWidth and m_effectiveHeight are
+  // current.
   void computeWhichControlsFit();
 
   // Node
@@ -221,8 +224,12 @@ class CORE_EXPORT MediaControls final : public HTMLDivElement {
   bool m_isMouseOverControls : 1;
   bool m_isPausedForScrubbing : 1;
 
-  TaskRunnerTimer<MediaControls> m_panelWidthChangedTimer;
-  int m_panelWidth;
+  // Watches the video element for resize and updates media controls as
+  // necessary.
+  Member<ResizeObserver> m_resizeObserver;
+
+  TaskRunnerTimer<MediaControls> m_elementSizeChangedTimer;
+  IntSize m_size;
 
   bool m_keepShowingUntilTimerFires : 1;
 };