Don't try to set the empty string as the preferred set.

Don't try to set the empty string as the preferred set.

Noticed during debugging that we did an extra MarkDocumentDirty() for
active stylesheet update trying to change the preferred set from empty
string to empty string in a document where no sheets had a title
attribute.

Guard the call sites which didn't check for emptiness and add a DCHECK
in the SetPreferredStylesheetSetNameIfNotSet implementation.

Review-Url: https://codereview.chromium.org/2879223002
Cr-Commit-Position: refs/heads/master@{#472039}
Committed: https://chromium.googlesource.com/chromium/src/+/55085162c036ab80c4392d24cca15c28d7456848

[rune, 2017-05-15 12:17:21]

The CQ bit was checked by rune@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2017-05-15 12:17:31]

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, 2017-05-15 13:38:10]

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

[commit-bot: I haz the power, 2017-05-15 13:38:10]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[rune, 2017-05-15 14:23:11]

rune@opera.com changed reviewers:
+ meade@chromium.org

[rune, 2017-05-15 14:23:11]

ptal

[meade_UTC10, 2017-05-16 07:09:02]

lgtm

[rune, 2017-05-16 08:01:17]

The CQ bit was checked by rune@opera.com

[commit-bot: I haz the power, 2017-05-16 08:02:15]

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, 2017-05-16 08:06:37]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1494921677038560, "parent_rev":
"8b051cce47275c3f36acda2646197cc2a31d053e", "commit_rev":
"55085162c036ab80c4392d24cca15c28d7456848"}

[commit-bot: I haz the power, 2017-05-16 08:06:46]

Description was changed from

==========
Don't try to set the empty string as the preferred set.

Noticed during debugging that we did an extra MarkDocumentDirty() for
active stylesheet update trying to change the preferred set from empty
string to empty string in a document where no sheets had a title
attribute.

Guard the call sites which didn't check for emptiness and add a DCHECK
in the SetPreferredStylesheetSetNameIfNotSet implementation.
==========

to

==========
Don't try to set the empty string as the preferred set.

Noticed during debugging that we did an extra MarkDocumentDirty() for
active stylesheet update trying to change the preferred set from empty
string to empty string in a document where no sheets had a title
attribute.

Guard the call sites which didn't check for emptiness and add a DCHECK
in the SetPreferredStylesheetSetNameIfNotSet implementation.

Review-Url: https://codereview.chromium.org/2879223002
Cr-Commit-Position: refs/heads/master@{#472039}
Committed:
https://chromium.googlesource.com/chromium/src/+/55085162c036ab80c4392d24cca1...
==========

[commit-bot: I haz the power, 2017-05-16 08:06:47]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/55085162c036ab80c4392d24cca1...