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

Source/core/layout/LayoutRubyRun.cpp

 /*
  * Copyright (C) 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 21 matching lines @@
 
 #include "core/layout/LayoutRubyRun.h"
 
 #include "core/layout/LayoutRubyBase.h"
 #include "core/layout/LayoutRubyText.h"
 #include "core/layout/LayoutText.h"
 
 namespace blink {
 
 LayoutRubyRun::LayoutRubyRun()
-    : LayoutBlockFlow(0)
+    : LayoutBlockFlow(nullptr)
 {
     setReplaced(true);
     setInline(true);
 }
 
 LayoutRubyRun::~LayoutRubyRun()
 {
 }
 
 bool LayoutRubyRun::hasRubyText() const
@@ skipping 146 matching lines @@
     RefPtr<ComputedStyle> newStyle = ComputedStyle::createAnonymousStyleWithDisplay(parentRuby->styleRef(), INLINE_BLOCK);
     rr->setStyle(newStyle.release());
     return rr;
 }
 
 LayoutObject* LayoutRubyRun::layoutSpecialExcludedChild(bool relayoutChildren, SubtreeLayoutScope& layoutScope)
 {
     // Don't bother positioning the LayoutRubyRun yet.
     LayoutRubyText* rt = rubyText();
     if (!rt)
-        return 0;
+        return nullptr;
     if (relayoutChildren)
         layoutScope.setChildNeedsLayout(rt);
     rt->layoutIfNeeded();
     return rt;
 }
 
 void LayoutRubyRun::layout()
 {
     LayoutBlockFlow::layout();
 
@@ skipping 76 matching lines @@
     // We can overhang the ruby by no more than half the width of the neighboring text
     // and no more than half the font size.
     int halfWidthOfFontSize = rubyText->style(firstLine)->fontSize() / 2;
     if (startOverhang)
         startOverhang = std::min<int>(startOverhang, std::min<int>(toLayoutText(startLayoutObject)->minLogicalWidth(), halfWidthOfFontSize));
     if (endOverhang)
         endOverhang = std::min<int>(endOverhang, std::min<int>(toLayoutText(endLayoutObject)->minLogicalWidth(), halfWidthOfFontSize));
 }
 
 } // namespace blink