Converts overview to use common ash types

ash/wm/common/wm_user_metrics_action.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_WM_COMMON_WM_USER_METRICS_ACTION_H_
 #define ASH_WM_COMMON_WM_USER_METRICS_ACTION_H_
 
 namespace ash {
 namespace wm {
 
 enum class WmUserMetricsAction {
   DRAG_MAXIMIZE_LEFT,
   DRAG_MAXIMIZE_RIGHT,
+  // Thumbnail sized overview of windows triggered by pressing the overview key.
+  WINDOW_OVERVIEW,
+
+  // User selected a window in overview mode different from the
+  // previously-active window.
+  WINDOW_OVERVIEW_ACTIVE_WINDOW_CHANGED,
+
+  // Selecting a window in overview mode by pressing the enter key.
+  WINDOW_OVERVIEW_ENTER_KEY,
 };
 
 }  // namespace wm
 }  // namespace ash
 
 #endif  // ASH_WM_COMMON_WM_USER_METRICS_ACTION_H_