Add null checks of GetImageObserver() in BitmapImage

Add null checks of GetImageObserver() in BitmapImage

Because GetImageObserver() can be null but some callsites have used it
without null checks.
This CL adds null checks to BitmapImage, while [1] adds to SVG-related
classes.

[1] https://codereview.chromium.org/2905833003/

BUG=726220
Review-Url: https://codereview.chromium.org/2906583003
Cr-Commit-Position: refs/heads/master@{#475147}
Committed: https://chromium.googlesource.com/chromium/src/+/1c33b530e841ad76be6e6c472711fda4e09c9d4d

[hiroshige, 2017-05-25 21:57:56]

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

[commit-bot: I haz the power, 2017-05-25 21:58:27]

Dry run: CQ is trying da patch.

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

[hiroshige, 2017-05-25 22:01:13]

Description was changed from

==========
Add null checks of GetImageObserver() in BitmapImage

BUG=
==========

to

==========
Add null checks of GetImageObserver() in BitmapImage

Because GetImageObserver() can be null, this CL adds null checks
where GetImageObserver() has been used originally without null checks.

BUG=726220
==========

[hiroshige, 2017-05-25 22:01:14]

hiroshige@chromium.org changed reviewers:
+ hajimehoshi@chromium.org, haraken@chromium.org, kouhei@chromium.org,
sigbjornf@opera.com

[hiroshige, 2017-05-25 22:06:24]

Description was changed from

==========
Add null checks of GetImageObserver() in BitmapImage

Because GetImageObserver() can be null, this CL adds null checks
where GetImageObserver() has been used originally without null checks.

BUG=726220
==========

to

==========
Add null checks of GetImageObserver() in BitmapImage

Because GetImageObserver() can be null but some callsites have used it
without null checks.
This CL adds null checks to BitmapImage, while [1] adds to SVG-related
classes.

[1] https://codereview.chromium.org/2905833003/

BUG=726220
==========

[hiroshige, 2017-05-25 22:18:02]

PTAL.

[haraken, 2017-05-25 22:18:46]

LGTM. Can we add a test?

[hiroshige, 2017-05-25 23:19:47]

On 2017/05/25 22:18:46, haraken wrote:
> LGTM. Can we add a test?

I haven't figure out specific cases to hit these null checks.
As BitmapImage::ShouldAnimate() checks GetImageObserver() to be non-null, it
would require GC to be invoked in a very specific timing.

[commit-bot: I haz the power, 2017-05-26 02:21:03]

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

[commit-bot: I haz the power, 2017-05-26 02:21:04]

Dry run: This issue passed the CQ dry run.

[kouhei (in TOK), 2017-05-26 11:14:14]

lgtm. I'm fine proceeding w/o test as I'm convinced this is subtle timing issue

[hiroshige, 2017-05-26 21:46:12]

The CQ bit was checked by hiroshige@chromium.org

[commit-bot: I haz the power, 2017-05-26 21:47:04]

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, 2017-05-26 21:52:18]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1495835172152600, "parent_rev":
"0ca6aab85a0d76d88a9333ed2618546fc1565025", "commit_rev":
"1c33b530e841ad76be6e6c472711fda4e09c9d4d"}

[commit-bot: I haz the power, 2017-05-26 21:52:29]

Description was changed from

==========
Add null checks of GetImageObserver() in BitmapImage

Because GetImageObserver() can be null but some callsites have used it
without null checks.
This CL adds null checks to BitmapImage, while [1] adds to SVG-related
classes.

[1] https://codereview.chromium.org/2905833003/

BUG=726220
==========

to

==========
Add null checks of GetImageObserver() in BitmapImage

Because GetImageObserver() can be null but some callsites have used it
without null checks.
This CL adds null checks to BitmapImage, while [1] adds to SVG-related
classes.

[1] https://codereview.chromium.org/2905833003/

BUG=726220

Review-Url: https://codereview.chromium.org/2906583003
Cr-Commit-Position: refs/heads/master@{#475147}
Committed:
https://chromium.googlesource.com/chromium/src/+/1c33b530e841ad76be6e6c472711...
==========

[commit-bot: I haz the power, 2017-05-26 21:52:31]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/1c33b530e841ad76be6e6c472711...