Prevent media controls from auto-hiding on audio-only content.

Source/core/html/shadow/MediaControls.cpp

 /*
  * Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011, 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 191 matching lines @@
     m_panel->makeOpaque();
 }
 
 void MediaControls::makeTransparent()
 {
     m_panel->makeTransparent();
 }
 
 bool MediaControls::shouldHideMediaControls()
 {
-    return !m_panel->hovered();
+    return !m_panel->hovered() && mediaElement().hasVideo();
 }
 
 void MediaControls::playbackStarted()
 {
     m_currentTimeDisplay->show();
     m_durationDisplay->hide();
 
     updatePlayState();
     m_timeline->setPosition(mediaElement().currentTime());
     updateCurrentTimeDisplay();
@@ skipping 209 matching lines @@
 
 void MediaControls::updateTextTrackDisplay()
 {
     if (!m_textDisplayContainer)
         createTextTrackDisplay();
 
     m_textDisplayContainer->updateDisplay();
 }
 
 }