views: Extract Widget observer into its own header file.

ash/system/web_notification/web_notification_tray.cc

 // Copyright (c) 2012 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 "ash/system/web_notification/web_notification_tray.h"
 
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/tray_bubble_view.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_views.h"
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "grit/ash_strings.h"
 #include "grit/ui_resources.h"
 #include "ui/aura/window.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/models/simple_menu_model.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/button/menu_button.h"
 #include "ui/views/controls/button/menu_button_listener.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/menu/menu_model_adapter.h"
 #include "ui/views/controls/menu/menu_runner.h"
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/layout/fill_layout.h"
 #include "ui/views/layout/grid_layout.h"
 #include "ui/views/painter.h"
+#include "ui/views/widget/widget_observer.h"
 
 namespace {
 
 // Tray constants
 const int kTrayContainerVeritcalPaddingBottomAlignment = 3;
 const int kTrayContainerHorizontalPaddingBottomAlignment = 1;
 const int kTrayContainerVerticalPaddingVerticalAlignment = 1;
 const int kTrayContainerHorizontalPaddingVerticalAlignment = 0;
 const int kPaddingFromLeftEdgeOfSystemTrayBottomAlignment = 8;
 const int kPaddingFromTopEdgeOfSystemTrayVerticalAlignment = 10;
@@ skipping 500 matching lines @@
 
   WebNotificationTray* tray_;
   internal::FixedSizedScrollView* scroller_;
   views::View* scroll_content_;
   internal::WebNotificationButtonView* button_view_;
 
   DISALLOW_COPY_AND_ASSIGN(BubbleContentsView);
 };
 
 class WebNotificationTray::Bubble : public internal::TrayBubbleView::Host,
-                                    public views::Widget::Observer {
+                                    public views::WidgetObserver {
  public:
   explicit Bubble(WebNotificationTray* tray)
       : tray_(tray),
         bubble_view_(NULL),
         bubble_widget_(NULL),
         contents_view_(NULL),
         ALLOW_THIS_IN_INITIALIZER_LIST(weak_ptr_factory_(this)) {
     views::View* anchor = tray->tray_container();
     views::BubbleBorder::ArrowLocation arrow_location;
     int arrow_offset = 0;
@@ skipping 60 matching lines @@
   }
 
   virtual void OnMouseExitedView() OVERRIDE {
   }
 
   virtual void OnClickedOutsideView() OVERRIDE {
     // May delete |this|.
     tray_->status_area_widget()->HideWebNotificationBubble();
   }
 
-  // Overridden from views::Widget::Observer.
+  // Overridden from views::WidgetObserver:
   virtual void OnWidgetClosing(views::Widget* widget) OVERRIDE {
     CHECK_EQ(bubble_widget_, widget);
     bubble_widget_ = NULL;
     tray_->HideBubble();  // Will destroy |this|.
   }
 
  private:
   void UpdateBubbleView() {
     contents_view_->Update(tray_->notification_list()->notifications());
     bubble_view_->Show();
@@ skipping 228 matching lines @@
   UpdateIcon();
   if (!bubble())
     return;
   if (GetNotificationCount() == 0)
     status_area_widget_->HideWebNotificationBubble();
   else
     bubble_->ScheduleUpdate();
 }
 
 }  // namespace ash