Add Skia on Chrome for Mac gyp rules

In addition to these rules, to build
the USE_SKIA_ON_MAC_CHROME variation,
define: gyp_defines='use_skia=1'

As is, this does not change any existing
platform, and has no new tests.

BUG=79463
TEST=none

Review URL: http://codereview.chromium.org/7219009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@89877 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed