GitLab

Cherry-pick with conflict of chromium
crrev.com/d7de03c45e06e104e3ba022e240f7bc88315e753

Conflicts:
	cc/layers/layer_impl.cc
	cc/layers/layer_impl.h
	cc/layers/picture_layer_impl.cc
	cc/layers/picture_layer_impl.h
	cc/resources/picture_layer_tiling.cc
	cc/resources/picture_layer_tiling.h
	cc/resources/tile_manager.cc
	cc/resources/tile_manager.h
	cc/trees/layer_tree_host_impl.cc
	cc/trees/layer_tree_impl.cc
	cc/trees/layer_tree_impl.h

BUG: 17315710

Original description:

This patch changes which tiles we report on. Previously, we logged
all of the available tiles. Now, we only log tiles that are active.
That is, only tiles that are on either active or pending trees are
logged.

The way this is done is as follows:
- Walk the tree, layers, tilings
- Insert all tiles from a tiling into a set
- Stuff those into a trace.

Change-Id: Ied16f30ee7e69873e12a2754054a39ecb7acc385