Sample mojo app using the compositor

This shows how to use cc from a mojo app. The GLES2 bindings are very sketchy
since we don't yet have an implementation of the command buffer support on top
of mojo pipes, but the rest is fairly reasonable.

Review URL: https://codereview.chromium.org/108853007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242261 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242261