MacViews: Create abstraction for event monitoring

ui/views/mouse_watcher_aura.cc

Index: ui/views/mouse_watcher_aura.cc
diff --git a/ui/views/mouse_watcher_aura.cc b/ui/views/mouse_watcher_aura.cc
deleted file mode 100644
index 03e05b625b13bba2fd4e489f55eab297ab80e722..0000000000000000000000000000000000000000
--- a/ui/views/mouse_watcher_aura.cc
+++ /dev/null
@@ -1,125 +0,0 @@
-// 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"
-
-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),
-        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 {
-    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)) {
-      // 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_;
-
-  // 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() {
-}
-
-MouseWatcherHost::~MouseWatcherHost() {
-}
-
-MouseWatcher::MouseWatcher(MouseWatcherHost* host,
-                           MouseWatcherListener* listener)
-    : host_(host),
-      listener_(listener),
-      notify_on_exit_time_(base::TimeDelta::FromMilliseconds(
-          kNotifyListenerTimeMs)) {
-}
-
-MouseWatcher::~MouseWatcher() {
-}
-
-void MouseWatcher::Start() {
-  if (!is_observing())
-    observer_.reset(new Observer(this));
-}
-
-void MouseWatcher::Stop() {
-  observer_.reset(NULL);
-}
-
-void MouseWatcher::NotifyListener() {
-  observer_.reset(NULL);
-  listener_->MouseMovedOutOfHost();
-}
-
-}  // namespace views