BUG=skia:

Review URL: https://codereview.chromium.org/683933003
Issue acquire barrier in SkRefCnt::unique().

When unique() returns true, it must also issue an acquire barrier.
Note that this change may adversly impact SkPath performance,
but editing SkPaths is already a performance issue.

BUG=chromium:258499

No API changes.
TBR=reed@google.com

Review URL: https://codereview.chromium.org/687293002
Fix bounds computation of all 0-input filters.

The SkRectShaderImageFilter had the same bug as previously fixed for
SkBitmapSource and SkPictureImageFilter. Rather than copy-and-paste
the implementation, this change makes all filters with 0 inputs return
their source bounds, instead of returning false.

BUG=427251

Review URL: https://codereview.chromium.org/681643003
MultiPictureDraw is taskgroup aware.
SampleApp is multipicturedraw aware.

BUG=skia:

Review URL: https://codereview.chromium.org/684923002
remove now unused (by Chrome) ifdef

BUG=skia:

Review URL: https://codereview.chromium.org/688043002
Separate out GrSurfaceConfig's fields from other structs used to create GrGL* subclasses of GrSurface.

BUG=skia:2889

Review URL: https://codereview.chromium.org/691523002
Revert of scale xmin/xmax etc in fontmetrics (patchset #1 id:1 of https://codereview.chromium.org/690533004/)

Reason for revert:
Breaking tests in Chromium, and not in a good way.

Original issue's description:
> scale xmin/xmax etc in fontmetrics
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/f8c2feffd68b3262f3c039ec1bd517c5f6cc9e4c

TBR=reed@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/686263002
Add a helper script to expose which version of adb the android scripts use.

Review URL: https://codereview.chromium.org/692633002