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

ui/wm/core/focus_controller.h

Index: ui/wm/core/focus_controller.h
diff --git a/ui/wm/core/focus_controller.h b/ui/wm/core/focus_controller.h
index 43d3c608b2138493f070bce4150b24a073edca58..95eac70892f5d0ce914c9e59dc9dad48cfee81ca 100644
--- a/ui/wm/core/focus_controller.h
+++ b/ui/wm/core/focus_controller.h
@@ -12,6 +12,7 @@
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/window_observer.h"
 #include "ui/events/event_handler.h"
+#include "ui/wm/public/activation_change_observer.h"
 #include "ui/wm/public/activation_client.h"
 #include "ui/wm/wm_export.h"
 
@@ -85,8 +86,10 @@ class WM_EXPORT FocusController : public aura::client::ActivationClient,
   // request (e.g. FocusWindow or ActivateWindow). It may be NULL, e.g. if
   // SetActiveWindow was not called by an external request. |activatable_window|
   // refers to the actual window to be activated, which may be different.
-  void SetActiveWindow(aura::Window* requested_window,
-                       aura::Window* activatable_window);
+  void SetActiveWindow(
+      aura::client::ActivationChangeObserver::ActivationReason reason,
+      aura::Window* requested_window,
+      aura::Window* activatable_window);
 
   // Called when a window's disposition changed such that it and its hierarchy
   // are no longer focusable/activatable. |next| is a valid window that is used
@@ -99,6 +102,10 @@ class WM_EXPORT FocusController : public aura::client::ActivationClient,
   // for the input window.
   void WindowFocusedFromInputEvent(aura::Window* window);
 
+  void FocusWindowImpl(
+      aura::client::ActivationChangeObserver::ActivationReason reason,
+      aura::Window* window);
+
   aura::Window* active_window_;
   aura::Window* focused_window_;