- Use new overflow chevron assets;
- Code drawing hover/pressed state and rotate image for left/right launcher;

BUG=132855
TEST=Verify launcher chevron uses new image and has hover effect similar to app menu and ubertray.

R=sky@chromium.org

Review URL: https://chromiumcodereview.appspot.com/10828184

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150272 0039d316-1c4b-4281-b951-d872f2087c98