Handle simple SkImageShaders

Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
BUG=667479
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Committed: https://crrev.com/6dfd1ba1efd6d4669b5f048eab38beaadfa63934
Cr-Commit-Position: refs/heads/master@{#436796}

[ericrk, 2016-11-21 02:28:41]

Description was changed from

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
==========

to

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

[ericrk, 2016-11-21 02:28:53]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-21 02:29:02]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-21 02:29:52]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-21 02:29:53]

Dry run: Try jobs failed on following builders:
  linux_precise_blink_rel on master.tryserver.blink (JOB_FAILED, no build URL)

[ericrk, 2016-11-21 02:39:13]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-21 02:39:21]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-21 02:40:12]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-21 02:40:13]

Dry run: Try jobs failed on following builders:
  linux_precise_blink_rel on master.tryserver.blink (JOB_FAILED, no build URL)

[ericrk, 2016-11-21 02:40:17]

Here's an attempt at handling SkImageShaders based on vmiura@'s SkPicture code.
Seems to work pretty well.

[ericrk, 2016-11-21 02:55:29]

The CQ bit was checked by ericrk@chromium.org

[commit-bot: I haz the power, 2016-11-21 02:55:42]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-21 02:55:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-21 02:55:43]

No L-G-T-M from a valid reviewer yet. 
CQ run can only be started by full committers or once the patch has
received an L-G-T-M from a full committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[ericrk, 2016-11-21 04:32:46]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-21 04:32:59]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-21 04:33:58]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-21 04:33:58]

Dry run: Try jobs failed on following builders:
  linux_precise_blink_rel on master.tryserver.blink (JOB_FAILED, no build URL)

[ericrk, 2016-11-21 18:21:45]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-21 18:22:20]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-21 18:24:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-21 18:24:50]

Dry run: Try jobs failed on following builders:
  linux_precise_blink_rel on master.tryserver.blink (JOB_FAILED, no build URL)

[ericrk, 2016-11-21 21:03:08]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-21 21:03:42]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-21 21:06:05]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-21 21:06:06]

Dry run: Try jobs failed on following builders:
  linux_precise_blink_rel on master.tryserver.blink (JOB_FAILED, no build URL)

[ericrk, 2016-11-21 21:08:09]

The CQ bit was unchecked by ericrk@chromium.org

[ericrk, 2016-11-21 21:08:21]

Description was changed from

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

to

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

[ericrk, 2016-11-21 21:08:28]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-21 21:08:50]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[ericrk, 2016-11-21 21:20:10]

Description was changed from

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

to

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
BUG=667479
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

[commit-bot: I haz the power, 2016-11-21 23:45:59]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-21 23:46:00]

Dry run: Try jobs failed on following builders:
  linux_trusty_blink_rel on master.tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_trusty_blink_rel/b...)

[ericrk, 2016-11-22 00:42:14]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-22 00:43:06]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-22 01:52:11]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-22 01:52:12]

Dry run: Try jobs failed on following builders:
  linux_trusty_blink_rel on master.tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_trusty_blink_rel/b...)

[ericrk, 2016-11-22 07:20:29]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-22 07:20:48]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-22 07:23:04]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-22 07:23:05]

Dry run: Try jobs failed on following builders:
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[ericrk, 2016-11-22 18:30:43]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-22 18:31:00]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-22 19:00:23]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-22 19:00:24]

Dry run: Try jobs failed on following builders:
  android_compile_dbg on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_comp...)

[ericrk, 2016-11-22 19:16:08]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-22 19:16:34]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-22 20:00:58]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-22 20:01:00]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[ericrk, 2016-11-22 22:02:48]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-22 22:03:45]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-22 22:09:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-22 22:09:50]

Dry run: Try jobs failed on following builders:
  chromium_presubmit on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[ericrk, 2016-11-28 22:51:53]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-28 22:52:38]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-28 22:57:40]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-28 22:57:41]

Dry run: Try jobs failed on following builders:
  linux_trusty_blink_rel on master.tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_trusty_blink_rel/b...)
  android_n5x_swarming_rel on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_n5x_...)
  ios-device on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device/builds...)
  ios-simulator on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/bui...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[ericrk, 2016-11-28 23:13:00]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-28 23:15:01]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-29 00:31:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-29 00:31:17]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_compile_dbg_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[ericrk, 2016-11-29 00:43:08]

Other than needing to rebase again :/, this should be good to go. vmpstr@, can
you take a look? Thanks!

[vmpstr, 2016-11-29 01:00:03]

lgtm, thanks!

https://codereview.chromium.org/2514263002/diff/140001/cc/playback/image_hija...
File cc/playback/image_hijack_canvas.cc (right):

https://codereview.chromium.org/2514263002/diff/140001/cc/playback/image_hija...
cc/playback/image_hijack_canvas.cc:99: matrix.preScale(1.f /
(decoded_image.scale_adjustment().width()),
nit: no need for brackets

[ericrk, 2016-11-29 21:46:05]

https://codereview.chromium.org/2514263002/diff/140001/cc/playback/image_hija...
File cc/playback/image_hijack_canvas.cc (right):

https://codereview.chromium.org/2514263002/diff/140001/cc/playback/image_hija...
cc/playback/image_hijack_canvas.cc:99: matrix.preScale(1.f /
(decoded_image.scale_adjustment().width()),
On 2016/11/29 01:00:03, vmpstr wrote:
> nit: no need for brackets

Done.

[ericrk, 2016-12-06 04:18:41]

Patchset #11 (id:200001) has been deleted

[ericrk, 2016-12-06 04:20:34]

Patchset #10 (id:180001) has been deleted

[ericrk, 2016-12-06 07:58:42]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-06 07:58:59]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-06 08:11:33]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-06 08:11:34]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)

[ericrk, 2016-12-06 18:26:08]

The CQ bit was checked by ericrk@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-06 18:26:33]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-06 20:26:06]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-06 20:26:08]

Dry run: This issue passed the CQ dry run.

[ericrk, 2016-12-06 21:16:05]

Ok, fixed an issue where we were not including the full scale when pre-decoding.
Now this impacts more layout tests (but nothing substantive). PTAL

[vmpstr, 2016-12-06 22:43:36]

lgtm

https://codereview.chromium.org/2514263002/diff/260001/cc/playback/discardabl...
File cc/playback/discardable_image_map.cc (right):

https://codereview.chromium.org/2514263002/diff/260001/cc/playback/discardabl...
cc/playback/discardable_image_map.cc:218: // TODO(ericrk): Handle cases where we
only need a sub-rect from the
Do you wanna file a bug for this and reference it here?

[ericrk, 2016-12-06 23:04:54]

The CQ bit was checked by ericrk@chromium.org

[commit-bot: I haz the power, 2016-12-06 23:05:34]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[ericrk, 2016-12-06 23:08:51]

https://codereview.chromium.org/2514263002/diff/260001/cc/playback/discardabl...
File cc/playback/discardable_image_map.cc (right):

https://codereview.chromium.org/2514263002/diff/260001/cc/playback/discardabl...
cc/playback/discardable_image_map.cc:218: // TODO(ericrk): Handle cases where we
only need a sub-rect from the
On 2016/12/06 22:43:36, vmpstr wrote:
> Do you wanna file a bug for this and reference it here?

Will add in a follow-up CL.

[ericrk, 2016-12-06 23:35:26]

The CQ bit was unchecked by ericrk@chromium.org

[ericrk, 2016-12-06 23:36:04]

The CQ bit was checked by ericrk@chromium.org

[commit-bot: I haz the power, 2016-12-06 23:37:04]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-07 00:52:01]

CQ is committing da patch.

Bot data: {"patchset_id": 260001, "attempt_start_ts": 1481067364003280,
"parent_rev": "5fc153f4d4e87722fe5dc78c8fabaa1763213a9b", "commit_rev":
"b8955342cba62749def1466332c55b2d87afed2e"}

[commit-bot: I haz the power, 2016-12-07 00:52:31]

Description was changed from

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
BUG=667479
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

to

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
BUG=667479
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

[commit-bot: I haz the power, 2016-12-07 00:52:33]

Committed patchset #12 (id:260001)

[commit-bot: I haz the power, 2016-12-07 00:56:40]

Description was changed from

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
BUG=667479
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

to

==========
Handle simple SkImageShaders

Currently, the Image Decode Controller (IDC) can't process images that
are embedded in a SkPaint's SkShader. This change expands coverage to
handle cases where the SkShader is a simple SkImageShader, for which
Skia provides introspection via isAImage().

This change updates DiscardableImageMap to allow us to track and pre-
decode these images. It additionally updates ImageHijackCanvas to
replace the un-decoded images with decoded ones at runtime.

This change does not yet handle decoding sub-rects of images used
in an SkImageShader, although that should be a relatively
straight-forward follow-up.

R=vmpstr,vmiura
BUG=667479
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Committed: https://crrev.com/6dfd1ba1efd6d4669b5f048eab38beaadfa63934
Cr-Commit-Position: refs/heads/master@{#436796}
==========

[commit-bot: I haz the power, 2016-12-07 00:56:42]

Patchset 12 (id:??) landed as
https://crrev.com/6dfd1ba1efd6d4669b5f048eab38beaadfa63934
Cr-Commit-Position: refs/heads/master@{#436796}