Revert of change SkDraw and all Blitters to use pixmap instead of bitmap

Revert of change SkDraw and all Blitters to use pixmap instead of bitmap (patchset #6 id:100001 of https://codereview.chromium.org/1148793007/)

Reason for revert:
speculative revert to try to unblock DEPS roll

Original issue's description:
> change SkDraw and all Blitters to use pixmap instead of bitmap
> 
> BUG=skia:
> 
> Committed: https://skia.googlesource.com/skia/+/c31af44336f5eb4a50e83e76e51962d46c3ed458

TBR=scroggo@google.com,jvanverth@google.com,reed@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Committed: https://skia.googlesource.com/skia/+/b3f0ec9f9967da2f80f0d842cb7fd53617b48de3

[reed2, 2015-06-09 02:57:36]

Created Revert of change SkDraw and all Blitters to use pixmap instead of bitmap

[commit-bot: I haz the power, 2015-06-09 02:57:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1164373003/1

[commit-bot: I haz the power, 2015-06-09 02:58:11]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/b3f0ec9f9967da2f80f0d842cb7fd53617b48de3

[reed2, 2015-06-09 04:44:43]

sample failure
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...