Make createWindow (mostly) work with OOPIF

Source/platform/PlatformScreen.cpp

 /*
  * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 62 matching lines @@
 }
 
 IntRect screenRect(Widget* widget)
 {
     HostWindow* hostWindow = toHostWindow(widget);
     if (!hostWindow)
         return IntRect();
     return IntRect(hostWindow->screenInfo().rect);
 }
 
-IntRect screenAvailableRect(Widget* widget)
+IntRect screenAvailableRect(const HostWindow& hostWindow)
 {
-    HostWindow* hostWindow = toHostWindow(widget);
-    if (!hostWindow)
-        return IntRect();
-    return IntRect(hostWindow->screenInfo().availableRect);
+    return IntRect(hostWindow.screenInfo().availableRect);
 }
 
 uint16_t screenOrientationAngle(Widget* widget)
 {
     HostWindow* hostWindow = toHostWindow(widget);
     if (!hostWindow)
         return 0;
     return hostWindow->screenInfo().orientationAngle;
 }
 
 WebScreenOrientationType screenOrientationType(Widget* widget)
 {
     HostWindow* hostWindow = toHostWindow(widget);
     if (!hostWindow)
         return WebScreenOrientationUndefined;
     return hostWindow->screenInfo().orientationType;
 }
 
 } // namespace blink