C++11: Replace 0 with nullptr where applicable in layout code.

Source/core/layout/LayoutThemeFontProviderWin.cpp

 /*
  * Copyright (C) 2012 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 18 matching lines @@
 #include "core/CSSValueKeywords.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/fonts/FontDescription.h"
 #include "platform/win/HWndDC.h"
 #include "platform/win/SystemInfo.h"
 #include "wtf/text/WTFString.h"
 #include <windows.h>
 
 #define SIZEOF_STRUCT_WITH_SPECIFIED_LAST_MEMBER(structName, member) \
     offsetof(structName, member) + \
-    (sizeof static_cast<structName*>(0)->member)
+    (sizeof static_cast<structName*>(nullptr)->member)
 #define NONCLIENTMETRICS_SIZE_PRE_VISTA \
     SIZEOF_STRUCT_WITH_SPECIFIED_LAST_MEMBER(NONCLIENTMETRICS, lfMessageFont)
 
 namespace blink {
 
 // Converts |points| to pixels. One point is 1/72 of an inch.
 static float pointsToPixels(float points)
 {
     static float pixelsPerInch = 0.0f;
     if (!pixelsPerInch) {
@@ skipping 113 matching lines @@
     }
 }
 
 // static
 void LayoutThemeFontProvider::setDefaultFontSize(int fontSize)
 {
     s_defaultFontSize = static_cast<float>(fontSize);
 }
 
 } // namespace blink