[Toolbar] Base toolbar button class with background images for button states

R=pkasting@chromium.org

Review URL: https://codereview.chromium.org/62873007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238218 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238218
Remove unused bookmark model helper function.

Forgot to delete this function in http://crrev.com/73463006.

BUG=

Review URL: https://codereview.chromium.org/90153003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238219 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238219