Clean up ColorRectProc plumbing.

Clean up ColorRectProc plumbing.

We've always been using the portable ColorRect32, so we don't need the 
ColorRectProc plumbing.

Furthermore, ColorRect32 doesn't seem to be very important (we're only using
it in the opaque case, which our row-by-row procs already specialize for).
Remove that too.

If we find we want specialization for really narrow rects again, let's put it in
blitRect() directly.  It's pretty unlikely we're going to get platform-specific
speedup for blits to non-contiguous memory.

My local SKP comparison is +- 3%... most neutral I've ever seen.


BUG=skia:

Committed: https://skia.googlesource.com/skia/+/edeccc58606e0421a1ae275e391ee4347c6f52f6

[mtklein_C, 2015-02-25 20:29:14]

mtklein@chromium.org changed reviewers:
+ reed@google.com

[reed1, 2015-02-25 20:38:35]

lgtm

[mtklein, 2015-02-25 20:39:25]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-02-25 20:40:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/959873002/20001

[commit-bot: I haz the power, 2015-02-25 20:53:01]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/edeccc58606e0421a1ae275e391ee4347c6f52f6