Fix crash in FontFaceSet::ready

Fix crash in FontFaceSet::ready

This fixes a crash introduced by http://crrev.com/2722493002.
FontFaceSet can outlive Document, so aliveness check is needed before
touching the document.

BUG=698776
Review-Url: https://codereview.chromium.org/2737733002
Cr-Commit-Position: refs/heads/master@{#455349}
Committed: https://chromium.googlesource.com/chromium/src/+/ac3c0012ce426716061dc073928f701fd64ff712

[Kunihiko Sakamoto, 2017-03-07 06:00:14]

Description was changed from

==========
Crash fix

Re-add inActiveDocumentContext() check removed at http://crrev.com/1313853003.
BUG=698776
==========

to

==========
Fix crash in FontFaceSet::ready

This fixes a crash introduced by http://crrev.com/2722493002.
FontFaceSet can outlive Document, so aliveness check is needed before
touching the document.
BUG=698776
==========

[Kunihiko Sakamoto, 2017-03-07 06:09:46]

Description was changed from

==========
Fix crash in FontFaceSet::ready

This fixes a crash introduced by http://crrev.com/2722493002.
FontFaceSet can outlive Document, so aliveness check is needed before
touching the document.
BUG=698776
==========

to

==========
Fix crash in FontFaceSet::ready

This fixes a crash introduced by http://crrev.com/2722493002.
FontFaceSet can outlive Document, so aliveness check is needed before
touching the document.

BUG=698776
==========

[Kunihiko Sakamoto, 2017-03-07 06:09:57]

Patchset #1 (id:1) has been deleted

[Kunihiko Sakamoto, 2017-03-07 06:10:16]

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

[commit-bot: I haz the power, 2017-03-07 06:10:54]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Kunihiko Sakamoto, 2017-03-07 06:26:34]

ksakamoto@chromium.org changed reviewers:
+ kojii@chromium.org

[commit-bot: I haz the power, 2017-03-07 07:52:14]

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

[commit-bot: I haz the power, 2017-03-07 07:52:15]

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_...)

[kojii, 2017-03-07 13:30:13]

lgtm, thank you for taking an immediate action!

[Kunihiko Sakamoto, 2017-03-08 00:28:24]

The CQ bit was checked by ksakamoto@chromium.org

[commit-bot: I haz the power, 2017-03-08 00:29:27]

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, 2017-03-08 02:20:46]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1488932904982420,
"parent_rev": "e7ed9a6836adb62a31fdcb13e37264352375b327", "commit_rev":
"ac3c0012ce426716061dc073928f701fd64ff712"}

[commit-bot: I haz the power, 2017-03-08 02:21:41]

Description was changed from

==========
Fix crash in FontFaceSet::ready

This fixes a crash introduced by http://crrev.com/2722493002.
FontFaceSet can outlive Document, so aliveness check is needed before
touching the document.

BUG=698776
==========

to

==========
Fix crash in FontFaceSet::ready

This fixes a crash introduced by http://crrev.com/2722493002.
FontFaceSet can outlive Document, so aliveness check is needed before
touching the document.

BUG=698776

Review-Url: https://codereview.chromium.org/2737733002
Cr-Commit-Position: refs/heads/master@{#455349}
Committed:
https://chromium.googlesource.com/chromium/src/+/ac3c0012ce426716061dc073928f...
==========

[commit-bot: I haz the power, 2017-03-08 02:21:42]

Committed patchset #1 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/ac3c0012ce426716061dc073928f...