UMA stats for stylus usage

ash/BUILD.gn

Index: ash/BUILD.gn
diff --git a/ash/BUILD.gn b/ash/BUILD.gn
index 4b2bef37ba70fba34c7dbc09854e4658222efeb2..5a8fd335bf2e83deb760cef5c28520274eb7200c 100644
--- a/ash/BUILD.gn
+++ b/ash/BUILD.gn
@@ -113,6 +113,8 @@ component("ash") {
     "common/material_design/material_design_controller.cc",
     "common/material_design/material_design_controller.h",
     "common/metrics/gesture_action_type.h",
+    "common/metrics/pointer_metrics_recorder.cc",
+    "common/metrics/pointer_metrics_recorder.h",
     "common/metrics/user_metrics_action.h",
     "common/multi_profile_uma.cc",
     "common/multi_profile_uma.h",
@@ -784,8 +786,6 @@ component("ash") {
     "wm/session_state_animator_impl.h",
     "wm/stacking_controller.cc",
     "wm/stacking_controller.h",
-    "wm/stylus_metrics_recorder.cc",
-    "wm/stylus_metrics_recorder.h",
     "wm/system_gesture_event_filter.cc",
     "wm/system_gesture_event_filter.h",
     "wm/system_modal_container_event_filter.cc",
@@ -820,6 +820,7 @@ component("ash") {
     "//ash/common/strings",
     "//ash/resources",
     "//ash/resources/vector_icons",
+    "//ash/shared:app_types",
   ]
   deps = [
     "//ash/autoclick/common:autoclick",
@@ -952,8 +953,6 @@ component("ash") {
       "touch/touchscreen_util.h",
       "virtual_keyboard_controller.cc",
       "virtual_keyboard_controller.h",
-      "wm/stylus_metrics_recorder.cc",
-      "wm/stylus_metrics_recorder.h",
     ]
   }
 
@@ -1396,6 +1395,7 @@ test("ash_unittests") {
     "common/frame/custom_frame_view_ash_unittest.cc",
     "common/frame/default_header_painter_unittest.cc",
     "common/material_design/material_design_controller_unittest.cc",
+    "common/metrics/pointer_metrics_recorder_unittest.cc",
     "common/popup_message_unittest.cc",
     "common/shelf/shelf_background_animator_unittest.cc",
     "common/shelf/shelf_button_pressed_metric_tracker_unittest.cc",
@@ -1616,6 +1616,7 @@ test("ash_unittests") {
 
       # Can't resize on Windows Ash. http://crbug.com/165962
       "autoclick/autoclick_unittest.cc",
+      "common/metrics/pointer_metrics_recorder_unittest.cc",

[sky, 2016/09/29 21:25:21]

What is chromeos specific about this test? If it really is chromeos specific I
would rather you not list it above and instead include it in the chromeos
section only (line 1596ish)

       "display/resolution_notification_controller_unittest.cc",
 
       # TODO(zork): fix this test to build on Windows. See: crosbug.com/26906