Cherry-pick: CC: Ensure recycle tree contains no 'active' tiles.

Cherry-pick of Chromium crrev.com/r226318

Conflicts:
	cc/layers/picture_layer_impl.cc

BUG: 11446261

Original description:

Active tilings become recycle tilings due to our tiling-swap
while activating. But some active tiles exist that are not
in the pending tree (due to invalidation).

We need to remove these tiles or reset their priorities,
as otherwise they will just take up memory in the Tile-
Manager.

This adds DidBecomeRecycled, which resets all active
priorities. Combined with DidBecomeActive, this should
eliminate any 'old active tiles' (that were active and were
invalidated) from being prioritized in the TileManager.

Change-Id: I9ecff16ebb3e7f94f341d6775db7cc1e970ecf95
5 files changed