MacViews: Create abstraction for event monitoring

ui/views/mouse_watcher.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/mouse_watcher.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/event_types.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
-#include "ui/aura/env.h"
-#include "ui/aura/window.h"
 #include "ui/events/event.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/event_handler.h"
 #include "ui/events/event_utils.h"
-#include "ui/gfx/screen.h"
+#include "ui/views/event_monitor.h"
 
 namespace views {
 
 // Amount of time between when the mouse moves outside the Host's zone and when
 // the listener is notified.
 const int kNotifyListenerTimeMs = 300;
 
 class MouseWatcher::Observer : public ui::EventHandler {
  public:
   explicit Observer(MouseWatcher* mouse_watcher)
       : mouse_watcher_(mouse_watcher),
+        event_monitor_(views::EventMonitor::Create(this)),
         notify_listener_factory_(this) {
-    aura::Env::GetInstance()->AddPreTargetHandler(this);
-  }
-
-  ~Observer() override {
-    aura::Env::GetInstance()->RemovePreTargetHandler(this);
   }
 
   // ui::EventHandler implementation:
-  void OnMouseEvent(ui::MouseEvent* event) override {
+  virtual void OnMouseEvent(ui::MouseEvent* event) override {
     switch (event->type()) {
       case ui::ET_MOUSE_MOVED:
       case ui::ET_MOUSE_DRAGGED:
         HandleMouseEvent(MouseWatcherHost::MOUSE_MOVE);
         break;
       case ui::ET_MOUSE_EXITED:
         HandleMouseEvent(MouseWatcherHost::MOUSE_EXIT);
         break;
       default:
         break;
     }
   }
 
  private:
   MouseWatcherHost* host() const { return mouse_watcher_->host_.get(); }
 
   // Called when a mouse event we're interested is seen.
   void HandleMouseEvent(MouseWatcherHost::MouseEventType event_type) {
     // It's safe to use last_mouse_location() here as this function is invoked
     // during event dispatching.
-    if (!host()->Contains(aura::Env::GetInstance()->last_mouse_location(),
-                          event_type)) {
+    if (!host()->Contains(EventMonitor::GetLastMouseLocation(), event_type)) {
       // Mouse moved outside the host's zone, start a timer to notify the
       // listener.
       if (!notify_listener_factory_.HasWeakPtrs()) {
         base::MessageLoop::current()->PostDelayedTask(
             FROM_HERE,
             base::Bind(&Observer::NotifyListener,
                        notify_listener_factory_.GetWeakPtr()),
             event_type == MouseWatcherHost::MOUSE_MOVE
                 ? base::TimeDelta::FromMilliseconds(kNotifyListenerTimeMs)
                 : mouse_watcher_->notify_on_exit_time_);
       }
     } else {
       // Mouse moved quickly out of the host and then into it again, so cancel
       // the timer.
       notify_listener_factory_.InvalidateWeakPtrs();
     }
   }
 
   void NotifyListener() {
     mouse_watcher_->NotifyListener();
     // WARNING: we've been deleted.
   }
 
  private:
   MouseWatcher* mouse_watcher_;
+  scoped_ptr<views::EventMonitor> event_monitor_;
 
   // A factory that is used to construct a delayed callback to the listener.
   base::WeakPtrFactory<Observer> notify_listener_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Observer);
 };
 
 MouseWatcherListener::~MouseWatcherListener() {
 }
 
@@ skipping 19 matching lines @@
 void MouseWatcher::Stop() {
   observer_.reset(NULL);
 }
 
 void MouseWatcher::NotifyListener() {
   observer_.reset(NULL);
   listener_->MouseMovedOutOfHost();
 }
 
 }  // namespace views