Have to invalidate the mute button when changing the volume

This is because the painting code in
RenderMediaControlsChromium.cpp:paintMediaMuteButton depends on the
volume, and that code gets called via RenderTheme, so nothing else can
invalidate the button.

(This is another regression from converting media controls
to new-flexbox in http://trac.webkit.org/changeset/142947)


Review URL: https://codereview.chromium.org/16132004

git-svn-id: svn://svn.chromium.org/blink/trunk@151687 bbb929c8-8fbe-4397-9dbb-9b2b20218538
4 files changed