Adding tileGrid scaled playback capability to gm.
Adding tileGrid scaled playback capability to gm.

BUG=http://code.google.com/p/skia/issues/detail?id=1021
Review URL: https://codereview.appspot.com/6937077

git-svn-id: e8541e15acce502a64c929015570ad1648e548cd@6898 2bbb7eff-a529-9590-31e7-b0007b416f81

Cue/skia,Cue/skia,Cue/skia,Cue/skia