Added null safety for CSSParserContext in CSSPropertyShapeUtils.

Added null safety for CSSParserContext in CSSProperty utils files.

Changed CSSParserContext argument from * to & for null safety and
readability. Call sites are currently guaranteed to not pass null as
they convert from const refs themselves.

BUG=668012
Review-Url: https://codereview.chromium.org/2878383002
Cr-Commit-Position: refs/heads/master@{#471702}
Committed: https://chromium.googlesource.com/chromium/src/+/2c1c51b6f4179133c0b5dbb03cc5d69837c5088a

[Bugs Nash, 2017-05-15 05:55:44]

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

[commit-bot: I haz the power, 2017-05-15 05:55:53]

Dry run: CQ is trying da patch.

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

[Bugs Nash, 2017-05-15 05:57:20]

bugsnash@chromium.org changed reviewers:
+ shend@chromium.org

[shend, 2017-05-15 05:58:25]

lgtm

[Bugs Nash, 2017-05-15 06:56:50]

bugsnash@chromium.org changed reviewers:
+ suzyh@chromium.org

[Bugs Nash, 2017-05-15 06:56:51]

+suzyh for owners

[suzyh_UTC10 (ex-contributor), 2017-05-15 07:17:12]

lgtm

[commit-bot: I haz the power, 2017-05-15 07:55:58]

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

[commit-bot: I haz the power, 2017-05-15 07:55:59]

Dry run: This issue passed the CQ dry run.

[Bugs Nash, 2017-05-15 08:43:10]

The CQ bit was checked by bugsnash@chromium.org

[commit-bot: I haz the power, 2017-05-15 08:43:26]

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 08:47:54]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1494837790982960, "parent_rev":
"06b9f76225c4771ec0f2807dde44ae2d46ddead7", "commit_rev":
"2c1c51b6f4179133c0b5dbb03cc5d69837c5088a"}

[commit-bot: I haz the power, 2017-05-15 08:48:16]

Description was changed from

==========
Added null safety for CSSParserContext in CSSProperty utils files.

Changed CSSParserContext argument from * to & for null safety and
readability. Call sites are currently guaranteed to not pass null as
they convert from const refs themselves.

BUG=668012
==========

to

==========
Added null safety for CSSParserContext in CSSProperty utils files.

Changed CSSParserContext argument from * to & for null safety and
readability. Call sites are currently guaranteed to not pass null as
they convert from const refs themselves.

BUG=668012

Review-Url: https://codereview.chromium.org/2878383002
Cr-Commit-Position: refs/heads/master@{#471702}
Committed:
https://chromium.googlesource.com/chromium/src/+/2c1c51b6f4179133c0b5dbb03cc5...
==========

[commit-bot: I haz the power, 2017-05-15 08:48:17]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/2c1c51b6f4179133c0b5dbb03cc5...