Reland Chrome power profiler service

This CL implemented part of chrome power profiler, including the service, data provider and observer base.

BUG=337138
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=255328

[Pan, 2014-03-05 10:08:19]

@pfeldman,
devtools part still need your lgtm, sorry to interrupt again.

@jam
please review the test case changes, thanks for your help.

thanks
Pan

https://codereview.chromium.org/187063007/diff/1/content/browser/power_profil...
File content/browser/power_profiler/power_profiler_service_unittest.cc (right):

https://codereview.chromium.org/187063007/diff/1/content/browser/power_profil...
content/browser/power_profiler/power_profiler_service_unittest.cc:57:
base::MessageLoop::current()->Quit();
This patch was reverted again due to our test hang on mac_valgrind and
linux_tsan.

I checked the behavior by linux tsan, MessageLoop::current()->Quit() doesn't
work as expected, it never quit the nested loop, (while it works quite well out
of valgrind), interesting.
and I found "Run()" and "Quit()" method in base/message_loop/message_loop.h is
deprecated, in crbug.com/131220, it says Quit leads to Timeout flakiness, while
RunLoop is encouraged to use instead.
So I updated this patch with RunLoop, it passed my local linux tsan and chromium
trybot linux_tsan. 
I think "Quit()" is the same reason for hang on mac_valgrind.

[jam, 2014-03-05 22:24:50]

lgtm

[Pan, 2014-03-05 22:52:30]

The CQ bit was checked by pan.deng@intel.com

[commit-bot: I haz the power, 2014-03-05 22:52:53]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pan.deng@intel.com/187063007/20001

[commit-bot: I haz the power, 2014-03-06 00:08:49]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pan.deng@intel.com/187063007/20001

[commit-bot: I haz the power, 2014-03-06 00:30:50]

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

[commit-bot: I haz the power, 2014-03-06 00:30:50]

Try jobs failed on following builders: mac_chromium_compile_dbg

[Pan, 2014-03-06 00:56:13]

The CQ bit was checked by pan.deng@intel.com

[commit-bot: I haz the power, 2014-03-06 00:59:06]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pan.deng@intel.com/187063007/20001

[commit-bot: I haz the power, 2014-03-06 02:53:54]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pan.deng@intel.com/187063007/20001

[commit-bot: I haz the power, 2014-03-06 03:18:26]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pan.deng@intel.com/187063007/20001

[commit-bot: I haz the power, 2014-03-06 04:01:34]

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

[commit-bot: I haz the power, 2014-03-06 04:01:35]

Try jobs failed on following builders: mac_chromium_compile_dbg

[Pan, 2014-03-06 04:51:12]

The CQ bit was checked by pan.deng@intel.com

[commit-bot: I haz the power, 2014-03-06 04:52:22]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pan.deng@intel.com/187063007/20001

[commit-bot: I haz the power, 2014-03-06 13:59:33]

Change committed as 255328