Change mac notifications UI to match the new mocks.  Introduce a new utility view which provides an image based button that changes on hover and press.

Refer to the bug for screenshots of the current and desired UI.
 
Screenshot of what results from this patch is visible at http://www.corp.google.com/~johnnyg/49490patch.png

XIB change: change height of title bar, change bindings of buttons.

BUG=49190
TEST=notifications on the mac

Review URL: http://codereview.chromium.org/3014004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@54326 0039d316-1c4b-4281-b951-d872f2087c98
14 files changed