Converts overview to use common ash types

ash/metrics/user_metrics_recorder.h

Index: ash/metrics/user_metrics_recorder.h
diff --git a/ash/metrics/user_metrics_recorder.h b/ash/metrics/user_metrics_recorder.h
index f372920d1f0fdf15709b0b6587b31c82c6b96378..985a8f848af19eba5aa41d9e6c63c0d8790a831b 100644
--- a/ash/metrics/user_metrics_recorder.h
+++ b/ash/metrics/user_metrics_recorder.h
@@ -127,16 +127,6 @@ enum UserMetricsAction {
   UMA_WINDOW_MAXIMIZE_BUTTON_MAXIMIZE_LEFT,
   UMA_WINDOW_MAXIMIZE_BUTTON_MAXIMIZE_RIGHT,
 
-  // Thumbnail sized overview of windows triggered by pressing the overview key.
-  UMA_WINDOW_OVERVIEW,
-
-  // User selected a window in overview mode different from the
-  // previously-active window.
-  UMA_WINDOW_OVERVIEW_ACTIVE_WINDOW_CHANGED,
-
-  // Selecting a window in overview mode by pressing the enter key.
-  UMA_WINDOW_OVERVIEW_ENTER_KEY,
-
   // Window selection started by beginning an alt+tab cycle. This does not count
   // each step through an alt+tab cycle.
   UMA_WINDOW_CYCLE,