cc: Fix tile manager raster tile iterator perftest.
This test is currently broken, as it doesn't really reset the initial
conditions each run.
NOTE TO PERF SHERIFFS
---------------------
This is very likely to regress all of the
tile_manager_raster_tile_iterator tests. This is expected, as the test
currently doesn't do anything useful. This is a correctness fix for
that test.
R=reveman, enne
Review URL: https://codereview.chromium.org/
283463003
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269885 0039d316-1c4b-4281-b951-d872f2087c98