Cherry pick Add gpu_memory_usage to Tile::AsValue

Will let us show gpu memory usage in a more-intuitive way in frame
viewer.

Review URL: https://codereview.chromium.org/447963004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287998
0039d316-1c4b-4281-b951-d872f2087c98

Chromium revision: d1cb7ee309cc97dc8ccbb95da4e57a44af5bc924
Bug: 17315710

Change-Id: I2dfe624bbd030e78a314290d2d1b0b84cbfb8167
1 file changed