Add missing UMA histograms for Startup.AppListFirstPaint*

Add missing UMA histograms for Startup.AppListFirstPaint*

These were added in http://crrev.com/218723 but without a histograms
change in src/tools/metrics/histograms or src-internal/tools/histograms.

The values cover the gap in measurement between when the app launcher
view is created and when it actually gets painted. Similar to
Startup.BrowserWindowDisplay.

BUG=274049
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=270069

[tapted, 2014-05-13 03:54:06]

@benwells: just checking we still want these before sending to OWNERS. I guess
we should examine the data collected first :)

[benwells, 2014-05-13 04:06:14]

On 2014/05/13 03:54:06, tapted wrote:
> @benwells: just checking we still want these before sending to OWNERS. I guess
> we should examine the data collected first :)

I think we should keep it. This is the kind of stuff which is gold when you want
it.

[benwells, 2014-05-13 04:06:25]

On 2014/05/13 04:06:14, benwells wrote:
> On 2014/05/13 03:54:06, tapted wrote:
> > @benwells: just checking we still want these before sending to OWNERS. I
guess
> > we should examine the data collected first :)
> 
> I think we should keep it. This is the kind of stuff which is gold when you
want
> it.

so, lgtm

[tapted, 2014-05-13 04:09:53]

+isherman. Hi Ilya, PTAL for OWNERS. This is following the pattern in use by the
existing Startup.ShowAppList* histograms

[Ilya Sherman, 2014-05-13 04:33:50]

LGTM

[tapted, 2014-05-13 04:45:44]

The CQ bit was checked by tapted@chromium.org

[commit-bot: I haz the power, 2014-05-13 04:46:26]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tapted@chromium.org/283603004/1

[commit-bot: I haz the power, 2014-05-13 11:47:27]

Change committed as 270069