UMA log NTP loading time separately for local, google and other NTPs.

Log NTP loading time separately for local, Google and other NTPs.

We currently use the same UMA metric to log the loading time of different kinds of NTP:
- The local NTP
- The Google app-cached NTP
- NTP from other providers

This CL separates these in three UMA metric using histogram suffixes.

In addition, this CL brings back the Tab.NewTab* UMA metrics to the public histograms.xml in accordance with the practice that metrics in the public chromium repository should be in the public histograms.xml.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=289946

[beaudoin, 2014-08-15 14:10:38]

Jered: That's a small CL cleaning up a UMA metric that I'm hoping to land before
the branch point, if you could take a quick look it would be appreciated.

Alexei: For histograms.xml

Thanks!

[Jered, 2014-08-15 14:53:16]

On 2014/08/15 14:10:38, beaudoin wrote:
> Jered: That's a small CL cleaning up a UMA metric that I'm hoping to land
before
> the branch point, if you could take a quick look it would be appreciated.
> 
> Alexei: For histograms.xml
> 
> Thanks!

lgtm

[Alexei Svitkine (slow), 2014-08-15 14:59:43]

lgtm, stamping since the branch point is so soon, but in the future it's better
to first move the XML definitions over in separate CLs and then make changes to
them.

https://codereview.chromium.org/474053002/diff/20001/tools/metrics/histograms...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/474053002/diff/20001/tools/metrics/histograms...
tools/metrics/histograms/histograms.xml:33410: +<histogram name="Tab.NewTab"
enum="NewTabType">
Please also send me a CL removing these histograms from the internal XML file.
Thanks!

[beaudoin, 2014-08-15 15:21:58]

The CQ bit was checked by beaudoin@chromium.org

[commit-bot: I haz the power, 2014-08-15 15:23:16]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/beaudoin@chromium.org/474053002/20001

[commit-bot: I haz the power, 2014-08-15 18:31:08]

Committed patchset #2 (20001) as 289946