[tracing] Re-enable mmaps dump provider for memory-infra

[tracing] Re-enable mmaps dump provider for memory-infra

As agreed during the offline meeting, it is OK for chrome://tracing
to get mmaps dumps into the trace data, as long as the infobar
indicating that an extension with the debugger permission is
using the devtools protocol is showed on all tabs.
The latter happened in crrev.com/1295493005 (see crbug.com/521686),
so this is effectively a revert of crrev.com/1275013005.

BUG=517906
Committed: https://crrev.com/c3e3255edf63003a1e559f50fe7f51325ce2051d
Cr-Commit-Position: refs/heads/master@{#347201}

[Primiano Tucci (use gerrit), 2015-09-01 14:01:04]

primiano@chromium.org changed reviewers:
+ jschuh@chromium.org, mdempsky@chromium.org

[Primiano Tucci (use gerrit), 2015-09-01 14:01:04]

mdempsky/jschuh this is a follow-up to our meeting 2015-08-14 "Chrome Memory
Dumping security issues".
As agreed I'm re-enabling the feature (mmaps into chrome://tracing without any
cmdline flag) as the required infobar UI change landed in crrev.com/1295493005.

[mdempsky, 2015-09-01 20:35:36]

LGTM

I skimmed the crbug.com/521686 and crrev.com/1295493005, and I agree they look
to have implemented what we agreed upon during the video call.

[Primiano Tucci (use gerrit), 2015-09-01 22:24:06]

primiano@chromium.org changed reviewers:
+ nduca@chromium.org

[Primiano Tucci (use gerrit), 2015-09-01 22:24:07]

+nduca for pre-flight stamp

[Primiano Tucci (use gerrit), 2015-09-03 08:58:09]

primiano@chromium.org changed reviewers:
+ dsinclair@chromium.org
- nduca@chromium.org

[Primiano Tucci (use gerrit), 2015-09-03 08:58:09]

+dsinclair

[dsinclair, 2015-09-03 13:40:46]

The CQ bit was checked by dsinclair@chromium.org

[dsinclair, 2015-09-03 13:40:47]

lgtm

[commit-bot: I haz the power, 2015-09-03 13:41:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1311163004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1311163004/1

[commit-bot: I haz the power, 2015-09-03 16:39:22]

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

[commit-bot: I haz the power, 2015-09-03 16:39:23]

Try jobs failed on following builders:
  linux_android_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_android_r...)

[Primiano Tucci (use gerrit), 2015-09-03 17:42:25]

The CQ bit was checked by primiano@chromium.org

[commit-bot: I haz the power, 2015-09-03 17:44:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1311163004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1311163004/1

[commit-bot: I haz the power, 2015-09-03 18:54:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-03 18:54:53]

Patchset 1 (id:??) landed as
https://crrev.com/c3e3255edf63003a1e559f50fe7f51325ce2051d
Cr-Commit-Position: refs/heads/master@{#347201}