cc: Change tile manager perftest to use layers.
Before this patch, the tile manager perftest would directly register
the tiles into tile manager in order to test. This provided accurate
numbers with regards to the number of tiles we had registered, but
it also coupled the knowledge that tile manager deals with tiles
directly.
This patch adds a bit of indirection to the perftest to create layers
that have tiles, and then call manage tiles. This decouples tile manager
from the perftest in the sense that the tile manager is free to choose
what it does with layers/tiles as the perftest better represents the
real world.
NOTE TO PERF SHERIFFS
---------------------
Please note that this changes TileManager perftest. In particular,
any changes in graphs to cc_perftests.manage_tiles should be
disregarded. This patch completely reworks the perftest, so
the results are not comparable to previous results.
Review URL: https://codereview.chromium.org/
284553002
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270922 0039d316-1c4b-4281-b951-d872f2087c98