Remove redundant DecodingImageGenerator::m_generationId

Remove redundant DecodingImageGenerator::m_generationId

The field was set based on the SkImage it is used to create. But it got
its ID from DecodingImageGenerator's subclass, SkImageGenerator.
Just use SkImageGenerator's uniqueID() method directly when needed.

No change in behavior. No new tests

Committed: https://crrev.com/08b5f549a45e0048000437b71976c754bbf26eab
Cr-Commit-Position: refs/heads/master@{#387312}

[scroggo_chromium, 2016-04-13 19:49:23]

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

[f(malita), 2016-04-14 12:38:35]

The CQ bit was checked by fmalita@chromium.org

[f(malita), 2016-04-14 12:38:35]

lgtm

[commit-bot: I haz the power, 2016-04-14 12:38:55]

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

[commit-bot: I haz the power, 2016-04-14 12:38:56]

This CL has an open dependency (Issue 1812273003 Patch 560001). Please resolve
the dependency and try again.
If you are sure that there is no real dependency, please use one of the options
listed in https://goo.gl/9Es4OR to land the CL.

[scroggo_chromium, 2016-04-14 13:22:12]

The CQ bit was checked by scroggo@chromium.org

[scroggo_chromium, 2016-04-14 13:22:12]

The patchset sent to the CQ was uploaded after l-g-t-m from fmalita@chromium.org
Link to the patchset: https://codereview.chromium.org/1887733003/#ps40001
(title: "Remove dependency")

[commit-bot: I haz the power, 2016-04-14 13:22:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1887733003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1887733003/40001

[commit-bot: I haz the power, 2016-04-14 14:39:28]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-04-14 14:40:45]

Description was changed from

==========
Remove redundant DecodingImageGenerator::m_generationId

The field was set based on the SkImage it is used to create. But it got
its ID from DecodingImageGenerator's subclass, SkImageGenerator.
Just use SkImageGenerator's uniqueID() method directly when needed.

No change in behavior. No new tests
==========

to

==========
Remove redundant DecodingImageGenerator::m_generationId

The field was set based on the SkImage it is used to create. But it got
its ID from DecodingImageGenerator's subclass, SkImageGenerator.
Just use SkImageGenerator's uniqueID() method directly when needed.

No change in behavior. No new tests

Committed: https://crrev.com/08b5f549a45e0048000437b71976c754bbf26eab
Cr-Commit-Position: refs/heads/master@{#387312}
==========

[commit-bot: I haz the power, 2016-04-14 14:40:46]

Patchset 3 (id:??) landed as
https://crrev.com/08b5f549a45e0048000437b71976c754bbf26eab
Cr-Commit-Position: refs/heads/master@{#387312}