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

ash/monitor/multi_monitor_manager.h

Index: ash/monitor/multi_monitor_manager.h
diff --git a/ash/monitor/multi_monitor_manager.h b/ash/monitor/multi_monitor_manager.h
index 2bbfcbb4b73cbdf8fd6c0acaf177cfac6694646d..688c184a92ef7e9cc0e22f7884f97b3335ccc60c 100644
--- a/ash/monitor/multi_monitor_manager.h
+++ b/ash/monitor/multi_monitor_manager.h
@@ -13,6 +13,10 @@
 #include "ui/aura/root_window_observer.h"
 #include "ui/aura/window.h"
 
+namespace gfx {
+class Monitor;
+}
+
 namespace ash {
 namespace internal {
 
@@ -35,16 +39,17 @@ class ASH_EXPORT MultiMonitorManager : public aura::MonitorManager,
 
   // MonitorManager overrides:
   virtual void OnNativeMonitorsChanged(
-      const std::vector<const aura::Monitor*>& monitors) OVERRIDE;
+      const std::vector<const gfx::Monitor*>& monitors) OVERRIDE;
   virtual aura::RootWindow* CreateRootWindowForMonitor(
-      aura::Monitor* monitor) OVERRIDE;
-  virtual const aura::Monitor* GetMonitorNearestWindow(
+      gfx::Monitor* monitor) OVERRIDE;
+  virtual gfx::Monitor* GetMonitorAt(size_t index) OVERRIDE;
+
+  virtual size_t GetNumMonitors() const OVERRIDE;
+  virtual const gfx::Monitor* GetMonitorNearestWindow(
       const aura::Window* window) const OVERRIDE;
-  virtual const aura::Monitor* GetMonitorNearestPoint(
+  virtual const gfx::Monitor* GetMonitorNearestPoint(
       const gfx::Point& point) const OVERRIDE;
-  virtual aura::Monitor* GetMonitorAt(size_t index) OVERRIDE;
-  virtual size_t GetNumMonitors() const OVERRIDE;
-  virtual aura::Monitor* GetMonitorNearestWindow(
+  virtual gfx::Monitor* GetMonitorNearestWindow(
       const aura::Window* window) OVERRIDE;
 
   // RootWindowObserver overrides:
@@ -52,7 +57,7 @@ class ASH_EXPORT MultiMonitorManager : public aura::MonitorManager,
                                    const gfx::Size& new_size) OVERRIDE;
 
  private:
-  typedef std::vector<aura::Monitor*> Monitors;
+  typedef std::vector<gfx::Monitor*> Monitors;
 
   void Init();
   void AddRemoveMonitorImpl();
@@ -63,7 +68,7 @@ class ASH_EXPORT MultiMonitorManager : public aura::MonitorManager,
   DISALLOW_COPY_AND_ASSIGN(MultiMonitorManager);
 };
 
-extern const aura::WindowProperty<aura::Monitor*>* const kMonitorKey;
+extern const aura::WindowProperty<gfx::Monitor*>* const kMonitorKey;
 
 }  // namespace internal
 }  // namespace ash