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

chrome/browser/notifications/balloon_collection_impl.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 "chrome/browser/notifications/balloon_collection_impl.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "chrome/browser/notifications/balloon.h"
@@ skipping 468 matching lines @@
   offset_to_move_above_panels_ = offset_to_move_above_panels;
   return true;
 }
 
 bool BalloonCollectionImpl::Layout::RefreshSystemMetrics() {
   bool changed = false;
 
 #if defined(OS_MACOSX)
   gfx::Rect new_work_area = GetMacWorkArea();
 #else
-  gfx::Rect new_work_area = gfx::Screen::GetPrimaryMonitorWorkArea();
+  gfx::Rect new_work_area = gfx::Screen::GetPrimaryMonitor().work_area();
 #endif
   if (!work_area_.Equals(new_work_area)) {
     work_area_.SetRect(new_work_area.x(), new_work_area.y(),
                        new_work_area.width(), new_work_area.height());
     changed = true;
   }
 
   return changed;
 }