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

ash/test/test_activation_delegate.cc

Index: ash/test/test_activation_delegate.cc
diff --git a/ash/test/test_activation_delegate.cc b/ash/test/test_activation_delegate.cc
index f583a05c3aa76be17396e58d53a27cb62362cc41..6f8caeff41a4d305ff44d8a05e4e08942fd67a8a 100644
--- a/ash/test/test_activation_delegate.cc
+++ b/ash/test/test_activation_delegate.cc
@@ -44,8 +44,10 @@ bool TestActivationDelegate::ShouldActivate() const {
   return activate_;
 }
 
-void TestActivationDelegate::OnWindowActivated(aura::Window* gained_active,
-                                               aura::Window* lost_active) {
+void TestActivationDelegate::OnWindowActivated(
+    aura::client::ActivationChangeObserver::ActivationReason reason,
+    aura::Window* gained_active,
+    aura::Window* lost_active) {
   DCHECK(window_ == gained_active || window_ == lost_active);
   if (window_ == gained_active) {
     activated_count_++;