Merge 250467 "Revert of Add UMA to track app launcher discoverab..."

Merge 250467 "Revert of Add UMA to track app launcher discoverab..."

> Revert of Add UMA to track app launcher discoverability. (https://codereview.chromium.org/143683004/)
> 
> Reason for revert:
> Doesn't compile Google Chrome-branded builds:
> 
> src\chrome\browser\ui\views\app_list\win\app_list_service_win.cc(459) : error C2660: 'AppListServiceImpl::EnableAppList' : function does not take 1 arguments
> 
> Original issue's description:
> > Add UMA to track app launcher discoverability.
> > 
> > We want to track effectiveness of the app launcher install education
> > pages in enabling users to find, and start using, the app launcher when
> > it is auto-enabled upon installing the first v2 packaged app. The
> > launcher is not auto-shown for the "first" install, to encourage users
> > to learn where it is.
> > 
> > This CL marks "how" the app launcher is enabled (e.g. command line flag,
> > webstore, etc.), and when the enable occurs. Then, when the user shows
> > the app list, the enable method and time taken to show it is recorded.
> > 
> > We also need to record users that "never" show the app list, or who see
> > the app list show automatically upon installing a _second_ app. One hour
> > is chosen as a timeout: if no value is recorded after one hour, a value
> > is recorded in the "last" bucket for the time taken.
> > 
> > BUG=314235
> > TBR=xiyuan@chromium.org
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=250348
> 
> TBR=benwells@chromium.org,xiyuan@chromium.org,tapted@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=314235
> 
> Review URL: https://codereview.chromium.org/134303006

TBR=grt@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=250533

[dxie, 2014-02-11 22:46:03]

Committed patchset #1 manually as r250533.