MacViews: Create abstraction for event monitoring

ui/views/event_monitor_aura.cc

+// Copyright 2014 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/views/event_monitor_aura.h"
+
+#include "base/logging.h"
+#include "ui/aura/env.h"
+
+namespace views {
+
+// static
+EventMonitor* EventMonitor::Create(ui::EventHandler* event_handler) {
+  return new EventMonitorAura(event_handler);
+}
+
+// static
+gfx::Point EventMonitor::GetLastMouseLocation() {
+  return aura::Env::GetInstance()->last_mouse_location();
+}
+
+EventMonitorAura::EventMonitorAura(ui::EventHandler* event_handler)
+    : event_handler_(event_handler) {
+  DCHECK(event_handler_);
+  aura::Env::GetInstance()->AddPreTargetHandler(event_handler_);
+}
+
+EventMonitorAura::~EventMonitorAura() {
+  aura::Env::GetInstance()->RemovePreTargetHandler(event_handler_);
+}
+
+}  // namespace views