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

ui/wm/core/window_activation_pre_target_handler.cc

Index: ui/wm/core/window_activation_pre_target_handler.cc
diff --git a/ui/wm/core/window_activation_pre_target_handler.cc b/ui/wm/core/window_activation_pre_target_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2e4793ff3aa2015e52485b59f3a75520774a3c23
--- /dev/null
+++ b/ui/wm/core/window_activation_pre_target_handler.cc
@@ -0,0 +1,60 @@
+// Copyright 2015 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.
+
+#include "ui/wm/core/window_activation_pre_target_handler.h"
+
+#include "ui/aura/window.h"
+#include "ui/events/event.h"
+#include "ui/events/event_constants.h"
+#include "ui/wm/core/window_activation_pre_target_handler_observer.h"
+#include "ui/wm/public/activation_client.h"
+
+namespace wm {
+
+WindowActivationPreTargetHandler::WindowActivationPreTargetHandler(
+    aura::client::ActivationClient* activation_client)
+    : activation_client_(activation_client) {
+}
+
+WindowActivationPreTargetHandler::~WindowActivationPreTargetHandler() {
+}
+
+void WindowActivationPreTargetHandler::AddObserver(
+    WindowActivationPreTargetHandlerObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void WindowActivationPreTargetHandler::RemoveObserver(
+    WindowActivationPreTargetHandlerObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+void WindowActivationPreTargetHandler::OnMouseEvent(ui::MouseEvent* event) {
+  if (event->type() == ui::ET_MOUSE_PRESSED && !event->handled())
+    ActivateWindowFromEvent(event);
+}
+
+void WindowActivationPreTargetHandler::OnGestureEvent(ui::GestureEvent* event) {
+  if (event->type() == ui::ET_GESTURE_BEGIN &&
+      event->details().touch_points() == 1 && !event->handled()) {
+    ActivateWindowFromEvent(event);
+  }
+}
+
+void WindowActivationPreTargetHandler::ActivateWindowFromEvent(
+    ui::Event* event) {
+  aura::Window* window = static_cast<aura::Window*>(event->target());
+  if (activation_client_->CanActivateWindow(window)) {
+    aura::Window* lost_active_window = activation_client_->GetActiveWindow();
+    FOR_EACH_OBSERVER(WindowActivationPreTargetHandlerObserver, observers_,
+                      BeforeWindowActivatedByPreTargetHandler());
+    activation_client_->ActivateWindow(window);
+    FOR_EACH_OBSERVER(
+        WindowActivationPreTargetHandlerObserver, observers_,
+        OnWindowActivatedByPreTargetHandler(
+            activation_client_->GetActiveWindow(), lost_active_window));
+  }
+}
+
+}  // namespace wm