Check frame for nullptr in AutoscrollController::animate

Check frame for nullptr in AutoscrollController::animate

BUG=361036
Committed: https://crrev.com/2f5ef2c20478b1c51bcde14129e3cfe3f9d2620c
Cr-Commit-Position: refs/heads/master@{#417280}

[sunyunjia, 2016-09-07 14:44:55]

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

[commit-bot: I haz the power, 2016-09-07 14:45:11]

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, 2016-09-07 15:27:04]

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

[commit-bot: I haz the power, 2016-09-07 15:27:04]

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

[sunyunjia, 2016-09-07 15:56:23]

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

[commit-bot: I haz the power, 2016-09-07 15:56:46]

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, 2016-09-07 16:28:31]

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

[commit-bot: I haz the power, 2016-09-07 16:28:32]

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

[sunyunjia, 2016-09-07 17:55:41]

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

[commit-bot: I haz the power, 2016-09-07 17:56:01]

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, 2016-09-07 18:42:44]

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

[commit-bot: I haz the power, 2016-09-07 18:42:45]

Dry run: Try jobs failed on following builders:
  win_chromium_compile_dbg_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_comp...)

[sunyunjia, 2016-09-07 20:47:04]

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

[commit-bot: I haz the power, 2016-09-07 20:47:58]

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, 2016-09-08 00:41:21]

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

[commit-bot: I haz the power, 2016-09-08 00:41:22]

Dry run: This issue passed the CQ dry run.

[sunyunjia, 2016-09-08 02:38:16]

Description was changed from

==========
Check nullptr for frame in AutoscrollController::animate

BUG=361036
==========

to

==========
Check nullptr for frame in AutoscrollController::animate

BUG=361036
==========

[sunyunjia, 2016-09-08 02:38:16]

sunyunjia@chromium.org changed reviewers:
+ bokan@chromium.org, dtapuska@chromium.org

[sunyunjia, 2016-09-08 02:38:57]

PTAL, Thanks!

[bokan, 2016-09-08 14:00:09]

lgtm

In the description, "check nullptr for frame" should be "check frame for
nullptr"

[sunyunjia, 2016-09-08 14:01:00]

Description was changed from

==========
Check nullptr for frame in AutoscrollController::animate

BUG=361036
==========

to

==========
Check frame for nullptr in AutoscrollController::animate

BUG=361036
==========

[sunyunjia, 2016-09-08 14:01:17]

The CQ bit was checked by sunyunjia@chromium.org

[commit-bot: I haz the power, 2016-09-08 14:01:49]

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, 2016-09-08 14:06:37]

Description was changed from

==========
Check frame for nullptr in AutoscrollController::animate

BUG=361036
==========

to

==========
Check frame for nullptr in AutoscrollController::animate

BUG=361036
==========

[commit-bot: I haz the power, 2016-09-08 14:06:38]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-09-08 14:09:35]

Description was changed from

==========
Check frame for nullptr in AutoscrollController::animate

BUG=361036
==========

to

==========
Check frame for nullptr in AutoscrollController::animate

BUG=361036

Committed: https://crrev.com/2f5ef2c20478b1c51bcde14129e3cfe3f9d2620c
Cr-Commit-Position: refs/heads/master@{#417280}
==========

[commit-bot: I haz the power, 2016-09-08 14:09:36]

Patchset 4 (id:??) landed as
https://crrev.com/2f5ef2c20478b1c51bcde14129e3cfe3f9d2620c
Cr-Commit-Position: refs/heads/master@{#417280}

[dtapuska, 2016-09-08 14:13:20]

https://codereview.chromium.org/2316113003/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/page/AutoscrollController.cpp (left):

https://codereview.chromium.org/2316113003/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/page/AutoscrollController.cpp:244: EventHandler&
eventHandler = m_autoscrollLayoutObject->frame()->eventHandler();
I was kind of anticipating a change like

LocalFrame* frame = m_autoscrollLayoutObject->frame();
if (!frame) {
  stopAutoscroll();
  return;
}
...

I think this can still cause a crash on line: 
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/page/Auto...

whereas the way I was thinking it wouldn't. Sorry for my delay on the review.