Media Controls: delegate 'volumechange' and 'focusin' handling to an EventListener.

third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp

Index: third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp b/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
index e60254555d49888e44e5603c68773519b13e9f57..50b5fc4f171622dd7aba04bc86b1ca28ab2e8b3c 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControlElements.cpp
@@ -299,7 +299,9 @@ void MediaControlMuteButtonElement::defaultEventHandler(Event* event) {
 }
 
 void MediaControlMuteButtonElement::updateDisplayType() {
-  setDisplayType(mediaElement().muted() ? MediaUnMuteButton : MediaMuteButton);
+  setDisplayType((mediaElement().muted() || mediaElement().volume() == 0)

[foolip, 2016/11/14 16:07:38]

Why this change? Clicking it will only toggle muted, looking at this I'd expect
it to also change the volume to 1 if it was 0.

[mlamouri (slow - plz ping), 2016/11/14 23:46:29]

Because we actually show a "muted" button if the volume is 0. I will add a
comment explaining. Hopefully, in the long run, this will be cleared out.

Added a comment for this.

+                     ? MediaUnMuteButton
+                     : MediaMuteButton);
   updateOverflowString();
 }