CC: Fix raster-on-demand (due to stale sort order).

Tile sort order dirty bit didn't respect tree priority
changes. This patch only updates GlobalState on ManageTiles,
to ensure the state is consistent with tile sorting.

BUG=295331
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/24269016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224994 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224994