Cleanup message_loop.cc

Cleanup message_loop.cc

Access kHexRangePrintingFlag through HistogramBase:: and not through instance variable. Accessing through instance variable is also correct, but confusing and can lead to future mistakes, because the variable is in this case null.
BUG=517586
Committed: https://crrev.com/0d2bf13aa9865bb69866033b98fb3b78f8b2dcc7
Cr-Commit-Position: refs/heads/master@{#342304}

[lucinka.brozkova, 2015-08-06 19:42:37]

lucinka.brozkova@gmail.com changed reviewers:
+ thestig@chromium.org

[lucinka.brozkova, 2015-08-06 19:42:38]

Hi,

Could you please review?

Thank you.

Lucie

[lucinka.brozkova, 2015-08-06 19:42:54]

The CQ bit was checked by lucinka.brozkova@gmail.com to run a CQ dry run

[commit-bot: I haz the power, 2015-08-06 19:44:04]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1278613003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1278613003/1

[commit-bot: I haz the power, 2015-08-06 19:44:05]

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

[commit-bot: I haz the power, 2015-08-06 19:44:05]

Dry run: No L-G-T-M from a valid reviewer yet. Only full committers are
accepted.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Lei Zhang, 2015-08-06 20:40:50]

lgtm

[lucinka.brozkova, 2015-08-07 04:27:46]

The CQ bit was checked by lucinka.brozkova@gmail.com

[commit-bot: I haz the power, 2015-08-07 04:28:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1278613003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1278613003/1

[commit-bot: I haz the power, 2015-08-07 05:41:21]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-07 05:42:27]

Patchset 1 (id:??) landed as
https://crrev.com/0d2bf13aa9865bb69866033b98fb3b78f8b2dcc7
Cr-Commit-Position: refs/heads/master@{#342304}