Done by extracting the PNG data from the ICO files, applying aggressive
optimization, and rebuilding the ICO.

Reduces the file size by 7443 bytes in total.

BUG=332639
R=oshima@chromium.org

Review URL: https://codereview.chromium.org/130163004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244089 0039d316-1c4b-4281-b951-d872f2087c98