[Media Controls] Prevent flicker when enter/exit fullscreen

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

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MediaControls_h
 #define MediaControls_h
 
 #include "core/CoreExport.h"
 #include "platform/heap/Handle.h"
 #include "platform/heap/Visitor.h"
@@ skipping 17 matching lines @@
   class Factory {
    public:
     virtual MediaControls* Create(HTMLMediaElement&, ShadowRoot&) = 0;
   };
 
   MediaControls(HTMLMediaElement&);
   virtual ~MediaControls() = default;
 
   HTMLMediaElement& MediaElement() const;
 
-  virtual void Show() = 0;
+  // Enables showing of the controls - only shows if appropriate.
+  virtual void MaybeShow() = 0;
+  // Disables showing of the controls - immediately hides.
   virtual void Hide() = 0;
+
   virtual void Reset() = 0;
 
   // Notify the media controls that the controlsList attribute has changed.
   virtual void OnControlsListUpdated() = 0;
 
   // TODO(mlamouri): this is temporary to notify the controls that an
   // HTMLTrackElement failed to load because there is no web exposed way to
   // be notified on the TextTrack object. See https://crbug.com/669977
   virtual void OnTrackElementFailedToLoad() = 0;
 
@@ skipping 18 matching lines @@
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   Member<HTMLMediaElement> media_element_;
 };
 
 }  // namespace blink
 
 #endif  // MediaControls_h