chrome/blink: Add functionality for in-product help for media elements.

third_party/WebKit/Source/modules/media_controls/elements/MediaControlInputElement.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 MediaControlInputElement_h
 #define MediaControlInputElement_h
 
 #include "core/html/HTMLInputElement.h"
 #include "modules/ModulesExport.h"
 #include "modules/media_controls/elements/MediaControlElementBase.h"
@@ skipping 29 matching lines @@
 
   // Returns a string representation of the media control element.
   // Subclasses should override this method to return the string representation
   // of the overflow button.
   virtual WebLocalizedString::Name GetOverflowStringName() const;
 
   // Implements a default event handler to record interaction on click.
   void DefaultEventHandler(Event*) override;
 
   // Implements MediaControlElementBase.
-  void UpdateShownState() final;
+  void UpdateShownState() override;
 
   // Updates the value of the Text string shown in the overflow menu.
   void UpdateOverflowString();
 
   // Record interaction if it wasn't recorded yet. It is used internally for
   // click events but also by some elements that have complex interaction logic.
   void MaybeRecordInteracted();
 
   // Returns whether this element is used for the overflow menu.
   bool IsOverflowElement() const;
@@ skipping 32 matching lines @@
 
   // Keeps track of whether the display/interaction have been recorded for the
   // CTR metrics.
   bool display_recorded_ = false;
   bool interaction_recorded_ = false;
 };
 
 }  // namespace blink
 
 #endif  // MediaControlInputElement_h