Media controls refer to less magic state.

third_party/WebKit/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
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     // Allow the theme to format the time.
     m_currentTimeDisplay->setInnerText(LayoutTheme::theme().formatMediaControlsCurrentTime(now, duration), IGNORE_EXCEPTION);
     m_currentTimeDisplay->setCurrentValue(now);
 }
 
 void MediaControls::updateVolume()
 {
     m_muteButton->updateDisplayType();
     // Invalidate the mute button because it paints differently according to volume.
-    if (LayoutObject* layoutObject = m_muteButton->layoutObject())
-        layoutObject->setShouldDoFullPaintInvalidation();
+    invalidate(m_muteButton);
 
     if (mediaElement().muted())
         m_volumeSlider->setVolume(0);
     else
         m_volumeSlider->setVolume(mediaElement().volume());
 
     // Update the visibility of our audio elements.
     // We never want the volume slider if there's no audio.
     // If there is audio, then we want it unless hiding audio is enabled and
     // we prefer to hide it.
     BatchedControlUpdate batch(this);
     m_volumeSlider->setIsWanted(mediaElement().hasAudio()
         && !(m_allowHiddenVolumeControls && preferHiddenVolumeControls(document())));
 
     // The mute button is a little more complicated.  If enableNewMediaPlaybackUi
     // is true, then we choose to hide or show the mute button to save space.
     // If enableNew* is not set, then we never touch the mute button, and
     // instead leave it to the CSS.
     // Note that this is why m_allowHiddenVolumeControls isn't rolled into prefer...().
     if (m_allowHiddenVolumeControls) {
         // If there is no audio track, then hide the mute button.
         m_muteButton->setIsWanted(mediaElement().hasAudio());
     }
 
     // Invalidate the volume slider because it paints differently according to volume.
-    if (LayoutObject* layoutObject = m_volumeSlider->layoutObject())
-        layoutObject->setShouldDoFullPaintInvalidation();
+    invalidate(m_volumeSlider);
 }
 
 void MediaControls::changedClosedCaptionsVisibility()
 {
     m_toggleClosedCaptionsButton->updateDisplayType();
 }
 
 void MediaControls::refreshClosedCaptionsButtonVisibility()
 {
     m_toggleClosedCaptionsButton->setIsWanted(mediaElement().hasClosedCaptions());
@@ skipping 245 matching lines @@
     }
 }
 
 void MediaControls::setAllowHiddenVolumeControls(bool allow)
 {
     m_allowHiddenVolumeControls = allow;
     // Update the controls visibility.
     updateVolume();
 }
 
+void MediaControls::invalidate(Element* element)
+{
+    if (!element)
+        return;
+
+    if (LayoutObject* layoutObject = element->layoutObject())
+        layoutObject->setShouldDoFullPaintInvalidation();
+}
+
+void MediaControls::networkStateChanged()
+{
+    invalidate(m_playButton);
+    invalidate(m_overlayPlayButton);
+    invalidate(m_muteButton);
+    invalidate(m_fullScreenButton);
+    invalidate(m_timeline);
+    invalidate(m_volumeSlider);
+}
+
 DEFINE_TRACE(MediaControls)
 {
     visitor->trace(m_mediaElement);
     visitor->trace(m_panel);
     visitor->trace(m_overlayPlayButton);
     visitor->trace(m_overlayEnclosure);
     visitor->trace(m_playButton);
     visitor->trace(m_currentTimeDisplay);
     visitor->trace(m_timeline);
     visitor->trace(m_muteButton);
     visitor->trace(m_volumeSlider);
     visitor->trace(m_toggleClosedCaptionsButton);
     visitor->trace(m_fullScreenButton);
     visitor->trace(m_durationDisplay);
     visitor->trace(m_enclosure);
     visitor->trace(m_castButton);
     visitor->trace(m_overlayCastButton);
     HTMLDivElement::trace(visitor);
 }
 
 }