Initial version rendering 2D path for O3D. This will eventually allow O3D apps to fall back to 2D logic on systems without (working) GPUs.
Incorporated 2D library Cairo to O3D.
Currently only support Linux and compiled when renderer = cairo.

TEST= I compiled with renderer = cairo and it worked. Also I compiled with renderer = gl and it worked.
BUG=none

Review URL: http://codereview.chromium.org/2825074

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55008 0039d316-1c4b-4281-b951-d872f2087c98