Moved scoped_histogram_timer to the main histogram_macros.h.

Moved scoped_histogram_timer to the main histogram_macros.h since this is broadly applicable.

Use the new timer for Profiler:GetProfile (a new histogram).

Of note: the data on chrome://tracing from TRACE_EVENT0("browser", "ProfileManager::GetProfile")
matches up very nicely with the data I get out of  Profile.GetProfile" on chrome://histograms.

Committed: https://crrev.com/7ebf4517633282e80158459e8056eb1c7dc26d69
Cr-Commit-Position: refs/heads/master@{#316227}

[rkaplow, 2015-02-12 22:20:14]

rkaplow@chromium.org changed reviewers:
+ asvitkine@chromium.org, rlp@chromium.org, xhwang@chromium.org

[rkaplow, 2015-02-12 22:22:06]

One comment:
I wanted to create a macro which handles both 
TRACE_EVENT0 and SCOPED_UMA_HISTOGRAM_TIMER, but when I did an include of
trace_event.h in the histogram_macros.h I was getting a strange error in
src/third_party/leveldatabase/chromium_logger.h that I couldn't really track
down.

[Alexei Svitkine (slow), 2015-02-12 22:28:16]

lgtm

[rkaplow, 2015-02-12 22:36:34]

New patchsets have been uploaded after l-g-t-m from asvitkine@chromium.org

[rkaplow, 2015-02-12 22:37:00]

rkaplow@chromium.org changed reviewers:
+ thakis@chromium.org

[DaleCurtis, 2015-02-12 22:40:53]

dalecurtis@chromium.org changed reviewers:
+ dalecurtis@chromium.org

[DaleCurtis, 2015-02-12 22:40:54]

\o/, my code has graduated to the big league :) lgtm

[rkaplow, 2015-02-12 23:26:10]

rkaplow@chromium.org changed reviewers:
+ mlerman@chromium.org
- rlp@chromium.org

[rpetterson, 2015-02-13 01:09:51]

rlp@chromium.org changed reviewers:
+ rlp@chromium.org

[rpetterson, 2015-02-13 01:09:52]

profiles LGTM

[Nico, 2015-02-13 03:01:08]

I got cc'd mid-cl and it's not clear to me what I'm supposed to do. If I'm here
to stamp base.gyp, that file lgtm

[rkaplow, 2015-02-13 03:08:55]

On 2015/02/13 03:01:08, Nico wrote:
> I got cc'd mid-cl and it's not clear to me what I'm supposed to do. If I'm
here
> to stamp base.gyp, that file lgtm

That was it. Thanks.

[Mike Lerman, 2015-02-13 13:43:59]

Not sure why I'm here with rlp? 

LGTM - profiles

[rkaplow, 2015-02-13 15:24:15]

New patchsets have been uploaded after l-g-t-m from
dalecurtis@chromium.org,rlp@chromium.org,thakis@chromium.org,mlerman@chromium...

[rkaplow, 2015-02-13 15:24:56]

The CQ bit was checked by rkaplow@chromium.org

[commit-bot: I haz the power, 2015-02-13 15:25:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/920963003/60001

[commit-bot: I haz the power, 2015-02-13 16:40:19]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-02-13 16:41:03]

Patchset 4 (id:??) landed as
https://crrev.com/7ebf4517633282e80158459e8056eb1c7dc26d69
Cr-Commit-Position: refs/heads/master@{#316227}