Refactor screen/monitor so that gfx::Screen returns monitor object.

ash/screen_ash.h

 // 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.
 
 #ifndef ASH_SCREEN_ASH_H_
 #define ASH_SCREEN_ASH_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "ash/ash_export.h"
 #include "ui/gfx/insets.h"
 #include "ui/gfx/screen.h"
 
 namespace aura {
 class RootWindow;
 }
 
 namespace ash {
 
 // Aura implementation of gfx::Screen. Implemented here to avoid circular
 // dependencies.
-class ASH_EXPORT ScreenAsh : public gfx::Screen {
+class ASH_EXPORT ScreenAsh : public gfx::ScreenImpl {
  public:
   explicit ScreenAsh(aura::RootWindow* root_window);
   virtual ~ScreenAsh();
 
   // Returns the bounds for maximized windows. Maximized windows trigger
   // auto-hiding the shelf.
   static gfx::Rect GetMaximizedWindowBounds(aura::Window* window);
 
   // Returns work area when a maximized window is not present.
   static gfx::Rect GetUnmaximizedWorkAreaBounds(aura::Window* window);
 
  protected:
-  virtual gfx::Point GetCursorScreenPointImpl() OVERRIDE;
-  virtual gfx::Rect GetMonitorWorkAreaNearestWindowImpl(
+  virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
+  virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
+
+  virtual int GetNumMonitors() OVERRIDE;
+  virtual const gfx::Monitor* GetMonitorNearestWindow(
       gfx::NativeView view) OVERRIDE;
-  virtual gfx::Rect GetMonitorAreaNearestWindowImpl(
-      gfx::NativeView view) OVERRIDE;
-  virtual gfx::Rect GetMonitorWorkAreaNearestPointImpl(
+  virtual const gfx::Monitor* GetMonitorNearestPoint(
       const gfx::Point& point) OVERRIDE;
-  virtual gfx::Rect GetMonitorAreaNearestPointImpl(
-      const gfx::Point& point) OVERRIDE;
-  virtual gfx::NativeWindow GetWindowAtCursorScreenPointImpl() OVERRIDE;
-  virtual gfx::Size GetPrimaryMonitorSizeImpl() OVERRIDE;
-  virtual int GetNumMonitorsImpl() OVERRIDE;
+  virtual const gfx::Monitor* GetPrimaryMonitor() OVERRIDE;
+
+  virtual void AddMonitorObserver(gfx::MonitorObserver* observer) OVERRIDE;
+  virtual void RemoveMonitorObserver(gfx::MonitorObserver* observer) OVERRIDE;
 
  private:
   aura::RootWindow* root_window_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenAsh);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SCREEN_ASH_H_