Ensure media control goes to transparent(hide) after seek by touch

Source/core/html/shadow/MediaControlElements.cpp

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 116 matching lines @@
 }
 
 void MediaControlPanelElement::transitionTimerFired(Timer<MediaControlPanelElement>*)
 {
     if (!m_opaque)
         hide();
 
     stopTimer();
 }
 
+bool MediaControlPanelElement::isOpaque()
+{
+    return m_opaque;
+}
+
 void MediaControlPanelElement::makeOpaque()
 {
     if (m_opaque)
         return;
 
     setInlineStyleProperty(CSSPropertyOpacity, 1.0, CSSPrimitiveValue::CSS_NUMBER);
     m_opaque = true;
 
     if (m_isDisplayed)
         show();
@@ skipping 562 matching lines @@
     float fontSize = smallestDimension * 0.05f;
     if (fontSize != m_fontSize) {
         m_fontSize = fontSize;
         setInlineStyleProperty(CSSPropertyFontSize, fontSize, CSSPrimitiveValue::CSS_PX);
     }
 }
 
 // ----------------------------
 
 } // namespace blink