Partial reland of "Add CHECK()s about ImageLoader::has_pending_load_event_"

Partial reland of "Add CHECK()s about ImageLoader::has_pending_load_event_"

Original CL:
https://codereview.chromium.org/2859383002/#ps220001

This CL relands the CHECK()s except for the failing one in
DispatchPendingErrorEvent().

Issue 722500 tracks the issue around DispatchPendingErrorEvent() and relanding
of the remaining CHECK().

Original CL description:
> As preparation for [1], this CL checks some assumptions to hold that
> are helpful for proving the equivalences in [1].
>
> [1] https://codereview.chromium.org/2859093003/
>
> BUG=624697, 719759
>
> Review-Url: https://codereview.chromium.org/2859383002
> Cr-Commit-Position: refs/heads/master@{#471464}
> Committed: https://chromium.googlesource.com/chromium/src/+/1b070387595668ec438ffec65185e61017300e3c

BUG=624697, 719759, 722500
Review-Url: https://codereview.chromium.org/2884773002
Cr-Commit-Position: refs/heads/master@{#471925}
Committed: https://chromium.googlesource.com/chromium/src/+/1c5d3f11a80d88d65f5fae8398ed97a7b5ea1508

[hiroshige, 2017-05-15 19:18:12]

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

[commit-bot: I haz the power, 2017-05-15 19:18:43]

Dry run: CQ is trying da patch.

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

[hiroshige, 2017-05-15 19:19:34]

Description was changed from

==========
Partial reland of "Add CHECK()s about ImageLoader::has_pending_load_event_"

This CL relands the CHECK()s except for the failing one in
DispatchPendingErrorEvent().

Issue 722500 tracks the issue around DispatchPendingErrorEvent() and relanding
of the remaining CHECK().

Original CL description:
> As preparation for [1], this CL checks some assumptions to hold that
> are helpful for proving the equivalences in [1].
>
> [1] https://codereview.chromium.org/2859093003/
>
> BUG=624697, 719759
>
> Review-Url: https://codereview.chromium.org/2859383002
> Cr-Commit-Position: refs/heads/master@{#471464}
> Committed:
https://chromium.googlesource.com/chromium/src/+/1b070387595668ec438ffec65185...

BUG=624697, 719759, 722500
==========

to

==========
Partial reland of "Add CHECK()s about ImageLoader::has_pending_load_event_"

Original CL:
https://codereview.chromium.org/2859383002/#ps220001

This CL relands the CHECK()s except for the failing one in
DispatchPendingErrorEvent().

Issue 722500 tracks the issue around DispatchPendingErrorEvent() and relanding
of the remaining CHECK().

Original CL description:
> As preparation for [1], this CL checks some assumptions to hold that
> are helpful for proving the equivalences in [1].
>
> [1] https://codereview.chromium.org/2859093003/
>
> BUG=624697, 719759
>
> Review-Url: https://codereview.chromium.org/2859383002
> Cr-Commit-Position: refs/heads/master@{#471464}
> Committed:
https://chromium.googlesource.com/chromium/src/+/1b070387595668ec438ffec65185...

BUG=624697, 719759, 722500
==========

[hiroshige, 2017-05-15 19:23:47]

hiroshige@chromium.org changed reviewers:
+ japhet@chromium.org, kinuko@chromium.org, kouhei@chromium.org,
yhirano@chromium.org

[hiroshige, 2017-05-15 19:23:47]

PTAL.

The diff from the original CL is that we don't insert CHECK() in
ImageLoader::DispatchPendingErrorEvent() (instead I put a comment there).

Because Issue 722500 looks need more time to fix, I'd like to reland remaining
CHECK()s before [1].

(In fact this CL and [1] don't have direct dependencies, I feel it's just nice
to have more asserts before [1] to catch potential regression bugs as assertion
failure)

[1] for SVG issue:
    https://codereview.chromium.org/2613853002/

[kouhei (in TOK), 2017-05-15 20:12:13]

lgtm

[kinuko, 2017-05-15 20:12:50]

lgtm

https://codereview.chromium.org/2884773002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/loader/ImageLoader.cpp (right):

https://codereview.chromium.org/2884773002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/loader/ImageLoader.cpp:665: // in-flight error
event tasks and we process only the first here.
whoa..

[commit-bot: I haz the power, 2017-05-15 21:44:18]

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

[commit-bot: I haz the power, 2017-05-15 21:44:19]

Dry run: This issue passed the CQ dry run.

[hiroshige, 2017-05-15 22:19:59]

The CQ bit was checked by hiroshige@chromium.org

[commit-bot: I haz the power, 2017-05-15 22:20:51]

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, 2017-05-15 22:29:02]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1494886799017090, "parent_rev":
"25d1b2958dad54c9310305dad0218c8f3fdbef98", "commit_rev":
"1c5d3f11a80d88d65f5fae8398ed97a7b5ea1508"}

[commit-bot: I haz the power, 2017-05-15 22:29:13]

Description was changed from

==========
Partial reland of "Add CHECK()s about ImageLoader::has_pending_load_event_"

Original CL:
https://codereview.chromium.org/2859383002/#ps220001

This CL relands the CHECK()s except for the failing one in
DispatchPendingErrorEvent().

Issue 722500 tracks the issue around DispatchPendingErrorEvent() and relanding
of the remaining CHECK().

Original CL description:
> As preparation for [1], this CL checks some assumptions to hold that
> are helpful for proving the equivalences in [1].
>
> [1] https://codereview.chromium.org/2859093003/
>
> BUG=624697, 719759
>
> Review-Url: https://codereview.chromium.org/2859383002
> Cr-Commit-Position: refs/heads/master@{#471464}
> Committed:
https://chromium.googlesource.com/chromium/src/+/1b070387595668ec438ffec65185...

BUG=624697, 719759, 722500
==========

to

==========
Partial reland of "Add CHECK()s about ImageLoader::has_pending_load_event_"

Original CL:
https://codereview.chromium.org/2859383002/#ps220001

This CL relands the CHECK()s except for the failing one in
DispatchPendingErrorEvent().

Issue 722500 tracks the issue around DispatchPendingErrorEvent() and relanding
of the remaining CHECK().

Original CL description:
> As preparation for [1], this CL checks some assumptions to hold that
> are helpful for proving the equivalences in [1].
>
> [1] https://codereview.chromium.org/2859093003/
>
> BUG=624697, 719759
>
> Review-Url: https://codereview.chromium.org/2859383002
> Cr-Commit-Position: refs/heads/master@{#471464}
> Committed:
https://chromium.googlesource.com/chromium/src/+/1b070387595668ec438ffec65185...

BUG=624697, 719759, 722500

Review-Url: https://codereview.chromium.org/2884773002
Cr-Commit-Position: refs/heads/master@{#471925}
Committed:
https://chromium.googlesource.com/chromium/src/+/1c5d3f11a80d88d65f5fae8398ed...
==========

[commit-bot: I haz the power, 2017-05-15 22:29:15]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/1c5d3f11a80d88d65f5fae8398ed...