Audio indicator in each tab

Basically a throbber animation that cycles over a number of
frames on a bitmap. Currently only 6 frames, which is too little
but good enough for testing.

Note that the tab.cc logic should make it so that the audio indicator
is low on the priority. That is, if the tab is recording or broadcasting and
playing sounds that should show instead of the audio animation.

BUG=3541
TEST=see bug

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=183977
Review URL: https://codereview.chromium.org/12328027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@184183 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed