GitLab

Adds necessary pieces to get the WebKit compositor working with
compositor_unittests target on Mac.  Required gyp build flags are:

    'use_aura': 1,
    'use_webkit_compositor': 1,
    'use_skia': 1,

BUG=104390, 104555
TEST=compositor_unittests --gtest_filter=LayerWithRealCompositorTest.* passes and shows correct visual results.

Review URL: http://codereview.chromium.org/8486020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@110875 0039d316-1c4b-4281-b951-d872f2087c98