Clean-up: Removes obsolete methods in gfx::Canvas.

Removes unused obsolete methods in gfx::Canvas.

I'm planning to remove gfx::Canvas::GetStringWidth(text, font) in a separate CL when I finish rewriting the client code.

BUG=265485
TEST=none

Review URL: https://codereview.chromium.org/141003013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247980 0039d316-1c4b-4281-b951-d872f2087c98
Add an empty message to the notification center.

This will now match the UI on Windows and ChromeOS.

BUG=284556

Review URL: https://codereview.chromium.org/142413005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247981 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247981
Replace mic key with search in a11y keyboard.

BUG=339196

Review URL: https://codereview.chromium.org/143153005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247983 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247983