Added UMA statistics for changing the active window via click or touch events.

ash/wm/workspace/workspace_layout_manager.h

 // Copyright (c) 2012 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_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_H_
 #define ASH_WM_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_H_
 
 #include <set>
 
 #include "ash/ash_export.h"
@@ skipping 66 matching lines @@
   void OnWindowPropertyChanged(aura::Window* window,
                                const void* key,
                                intptr_t old) override;
   void OnWindowStackingChanged(aura::Window* window) override;
   void OnWindowDestroying(aura::Window* window) override;
   void OnWindowBoundsChanged(aura::Window* window,
                              const gfx::Rect& old_bounds,
                              const gfx::Rect& new_bounds) override;
 
   // aura::client::ActivationChangeObserver overrides:
-  void OnWindowActivated(aura::Window* gained_active,
-                         aura::Window* lost_active) override;
+  void OnWindowActivated(
+      aura::client::ActivationChangeObserver::ActivationReason reason,
+      aura::Window* gained_active,
+      aura::Window* lost_active) override;
 
   // keyboard::KeyboardControllerObserver overrides:
   void OnKeyboardBoundsChanging(const gfx::Rect& new_bounds) override;
 
   // WindowStateObserver overrides:
   void OnPostWindowStateTypeChange(wm::WindowState* window_state,
                                    wm::WindowStateType old_type) override;
 
  private:
   typedef std::set<aura::Window*> WindowSet;
@@ skipping 42 matching lines @@
   // A window which covers the full container and which gets inserted behind the
   // topmost visible window.
   scoped_ptr<WorkspaceLayoutManagerDelegate> backdrop_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkspaceLayoutManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_H_