BUG=129203
TEST=Run chrome with --force-device-scale-factor=2 and go to bookmark manager, folder icons are high dpi.

Review URL: https://chromiumcodereview.appspot.com/10855106

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151258 0039d316-1c4b-4281-b951-d872f2087c98