Add metrics for WallpaperPicker launch source

 - Add a launch source which come from settings search

Bug: 183071440
Test: make statsd_testdrive; statsd_testdrive 179
Change-Id: I69a1a875f3a2f31d0158cabd80db8b5abefeb079
1 file changed
tree: 74dce3a9e8cbec90bc31a7910e1780bc2d352276
  1. stats/
  2. OWNERS