Revert of Revert[2] of add ImageShader, sharing code with its Bitmap cousin

Revert of Revert[2] of add ImageShader, sharing code with its Bitmap cousin (patchset #11 id:200001 of https://codereview.chromium.org/1352293002/ )

Reason for revert:
guess: Need to handle NPOT support in shader case

Original issue's description:
> Revert[2] of add ImageShader, sharing code with its Bitmap cousin
> 
> Adjustment from previous land : runtime check for npot-support when texture is requested for tiling.
> 
> (patchset #10 id:180001 of https://codereview.chromium.org/1342113002/ )
> 
> This reverts commit f2608513626264459a00388537175600b515cae2.
> 
> BUG=skia:4365
> 
> Committed: https://skia.googlesource.com/skia/+/fe05707c356d2a8c2c69222591d4cafbd456b4e5

TBR=fmalita@chromium.org,robertphillips@google.com,bsalomon@google.com,reed@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4365
Committed: https://skia.googlesource.com/skia/+/476506d070dbc59b158acc1a00c34bff95ab2968

[reed1, 2015-09-28 17:26:35]

Created Revert of Revert[2] of add ImageShader, sharing code with its Bitmap
cousin

[commit-bot: I haz the power, 2015-09-28 17:26:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1375673002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1375673002/1

[commit-bot: I haz the power, 2015-09-28 17:26:54]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/476506d070dbc59b158acc1a00c34bff95ab2968