Update straggling ImageSource references

Update straggling ImageSource references

GIFImageReader no longer needs ImageSource to compile, so stop
including it.

Update ImageDecodeBench to use the enums in ImageDecoder, so it can
build once again.

These were missed in crrev.com/1242023004

No change in behavior, no new tests.

BUG=439655
Committed: https://crrev.com/322d253ac9989e6020f69ed96ddb1d71e61cdb9e
git-svn-id: svn://svn.chromium.org/blink/trunk@199491 bbb929c8-8fbe-4397-9dbb-9b2b20218538

[scroggo_chromium, 2015-07-23 20:17:37]

scroggo@chromium.org changed reviewers:
+ noel@chromium.org

[Noel Gordon, 2015-07-24 02:16:48]

LGTM

[scroggo, 2015-07-24 15:14:17]

The CQ bit was checked by scroggo@google.com

[commit-bot: I haz the power, 2015-07-24 15:14:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1247033008/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1247033008/1

[commit-bot: I haz the power, 2015-07-24 15:18:54]

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

[commit-bot: I haz the power, 2015-07-24 15:18:55]

Try jobs failed on following builders:
  blink_presubmit on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/blink_presubmit/builds/3...)

[scroggo_chromium, 2015-07-24 16:02:31]

scroggo@chromium.org changed reviewers:
+ tkent@chromium.org

[scroggo_chromium, 2015-07-24 16:02:31]

Can I get an OWNERS review?

[scroggo_chromium, 2015-07-24 16:02:42]

On 2015/07/24 16:02:31, scroggo_chromium wrote:
> Can I get an OWNERS review?

(for Source/web)

[tkent, 2015-07-26 23:42:35]

The CQ bit was checked by tkent@chromium.org

[tkent, 2015-07-26 23:42:35]

lgtm

[commit-bot: I haz the power, 2015-07-26 23:42:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1247033008/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1247033008/1

[commit-bot: I haz the power, 2015-07-27 07:12:34]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=199491

[commit-bot: I haz the power, 2015-09-23 11:47:53]

Patchset 1 (id:??) landed as
https://crrev.com/322d253ac9989e6020f69ed96ddb1d71e61cdb9e