Add ScopedTrackers to measure the jank of base::Thread::StartWithOptions().

Add ScopedTrackers to measure the jank of base::Thread::StartWithOptions().

BUG=465458
Committed: https://crrev.com/f653ac3a6c48ebda5fc4464026ccbe04afba3e87
Cr-Commit-Position: refs/heads/master@{#319803}

[eroman, 2015-03-09 20:26:20]

eroman@chromium.org changed reviewers:
+ pkasting@chromium.org

[Peter Kasting, 2015-03-09 20:42:48]

I wouldn't bother; we already know this is janky, see my comment on the bug you
filed.

[Peter Kasting, 2015-03-09 20:43:33]

On 2015/03/09 20:42:48, Peter Kasting wrote:
> I wouldn't bother; we already know this is janky, see my comment on the bug
you
> filed.

I take that back.  We know this is janky, but adding these trackers would
probably allow us to remove others and close their bugs when they're just dupes
of this.  Go for it if that's your plan.

[eroman, 2015-03-09 21:08:53]

Right. Since nested scoped trackers subtract, this may cause other unknown jank
sources to go to zero, revealing the root problem to be this.

[eroman, 2015-03-09 21:08:54]

Right. Since nested scoped trackers subtract, this may cause other unknown jank
sources to go to zero, revealing the root problem to be this.

[eroman, 2015-03-09 21:39:17]

eroman@chromium.org changed reviewers:
+ rvargas@chromium.org

[eroman, 2015-03-09 21:39:18]

+rvargas as a base/OWNERS

[rvargas (doing something else), 2015-03-09 23:52:21]

lgtm

[eroman, 2015-03-09 23:55:00]

The CQ bit was checked by eroman@chromium.org

[commit-bot: I haz the power, 2015-03-09 23:56:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/987163002/1

[commit-bot: I haz the power, 2015-03-10 01:06:26]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-10 01:08:57]

Patchset 1 (id:??) landed as
https://crrev.com/f653ac3a6c48ebda5fc4464026ccbe04afba3e87
Cr-Commit-Position: refs/heads/master@{#319803}