Add keyboard icon resources for Android Chromoting client.

Also add a README file to document where the icons came from, along with
the right-to-use text.

R=jamiewalch@chromium.org

Review URL: https://codereview.chromium.org/178933002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253032 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253032