Enforce thread-safety of bitmaps in pictures via the type.

No runtime difference here, but it makes it impossible to forget to make
a shallow copy; you can't get at the full bitmap without it.

NOTREECHECKS=true

BUG=skia:

Review URL: https://codereview.chromium.org/799603002
Add parameter to specify gyp dir to gyp_to_android.

NOTRY=true
NOTREECHECKS=True
BUG=skia:3233

Review URL: https://codereview.chromium.org/800573002
new hairlines gm unstable on hd2000

NOTRY=True
TBR=
BUG=skia:

Review URL: https://codereview.chromium.org/800543002
Update GM to permit correctness testing of MPD on the GMs

Review URL: https://codereview.chromium.org/794273003
Create xfer processor backend.

This includes:
-Having an actual XP stage at the end of the gl pipeline.
-All Blending work is handled by XP until actually setting GL blend states
-GLPrograms test to test XP

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/4dffc940c430eec66d4707490eace19c9b3f7904

Review URL: https://codereview.chromium.org/764643004
Increase timeout on sfgate pageset

TBR=scroggo
NOTRY=true
BUG=skia:3196

Review URL: https://codereview.chromium.org/800563002
Fix some win64 warnings.

Review URL: https://codereview.chromium.org/795223002