Add always-threaded SkRecord quilt tests.

Now that we're drawing tiles threaded like implside painting, remove the checks
that those lock counts are balanced.  They're just not right for anyone anymore.

SkBitmaps themselves are not threadsafe (even const ones), so shallow copy them
on playback of an SkRecord.  (The underlying SkPixelRefs are threadsafe.)

Simplify quilt drawing by using SkBitmap::extractSubset.  No need for locking.

Bump up to 256x256 tiles.  16x16 tiles just murders performance (way too much
contention).  This has the nice side effect of letting us enable a bunch more
GMs for quilt mode; they drew wrong with small tiles but exactly right with large.

BUG=171776
R=reed@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/371023005
33 files changed