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

extensions/shell/browser/shell_desktop_controller_aura.cc

Index: extensions/shell/browser/shell_desktop_controller_aura.cc
diff --git a/extensions/shell/browser/shell_desktop_controller_aura.cc b/extensions/shell/browser/shell_desktop_controller_aura.cc
index 5ab8a3c8d25ab72aa9d97ae58e63bb7ee8d7b032..2a08fb7fc15e969bcd1faa2ebf81326f0f6eab02 100644
--- a/extensions/shell/browser/shell_desktop_controller_aura.cc
+++ b/extensions/shell/browser/shell_desktop_controller_aura.cc
@@ -35,6 +35,7 @@
 #include "ui/wm/core/input_method_event_filter.h"
 #include "ui/wm/core/native_cursor_manager.h"
 #include "ui/wm/core/native_cursor_manager_delegate.h"
+#include "ui/wm/core/window_activation_pre_target_handler.h"
 
 #if defined(OS_CHROMEOS)
 #include "chromeos/dbus/dbus_thread_manager.h"
@@ -255,9 +256,12 @@ void ShellDesktopControllerAura::InitWindowManager() {
   wm::FocusController* focus_controller =
       new wm::FocusController(new AppsFocusRules());
   aura::client::SetFocusClient(host_->window(), focus_controller);
-  host_->window()->AddPreTargetHandler(focus_controller);
   aura::client::SetActivationClient(host_->window(), focus_controller);
   focus_client_.reset(focus_controller);
+  window_activation_pretarget_handler_.reset(
+      new wm::WindowActivationPreTargetHandler(focus_controller));
+  host_->window()->AddPreTargetHandler(
+      window_activation_pretarget_handler_.get());
 
   input_method_filter_.reset(
       new wm::InputMethodEventFilter(host_->GetAcceleratedWidget()));
@@ -321,11 +325,11 @@ void ShellDesktopControllerAura::DestroyRootWindow() {
   host_->RemoveObserver(this);
   if (input_method_filter_)
     root_window_event_filter_->RemoveHandler(input_method_filter_.get());
-  wm::FocusController* focus_controller =
-      static_cast<wm::FocusController*>(focus_client_.get());
-  if (focus_controller) {
-    host_->window()->RemovePreTargetHandler(focus_controller);
+  if (window_activation_pretarget_handler_) {
+    host_->window()->RemovePreTargetHandler(
+        window_activation_pretarget_handler_.get());
     aura::client::SetActivationClient(host_->window(), NULL);
+    window_activation_pretarget_handler_.reset();
   }
   root_window_event_filter_.reset();
   capture_client_.reset();