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

Source/core/layout/LayoutMultiColumnFlowThreadTest.cpp

 // Copyright 2014 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 "config.h"
 
 #include "core/layout/LayoutMultiColumnFlowThread.h"
 
 #include "core/layout/LayoutMultiColumnSet.h"
 #include "core/layout/LayoutMultiColumnSpannerPlaceholder.h"
@@ skipping 15 matching lines @@
     String columnSetSignature(LayoutMultiColumnFlowThread*);
     String columnSetSignature(const char* multicolId);
 
     void setMulticolHTML(const String&);
 };
 
 LayoutMultiColumnFlowThread* MultiColumnRenderingTest::findFlowThread(const char* id) const
 {
     Node* multicol = document().getElementById(id);
     if (!multicol)
-        return 0;
+        return nullptr;
     LayoutBlockFlow* multicolContainer = toLayoutBlockFlow(multicol->layoutObject());
     if (!multicolContainer)
-        return 0;
+        return nullptr;
     return multicolContainer->multiColumnFlowThread();
 }
 
 String MultiColumnRenderingTest::columnSetSignature(LayoutMultiColumnFlowThread* flowThread)
 {
     String signature = "";
     for (LayoutBox* columnBox = flowThread->firstMultiColumnBox();
         columnBox;
         columnBox = columnBox->nextSiblingMultiColumnBox()) {
         if (columnBox->isLayoutMultiColumnSpannerPlaceholder())
@@ skipping 287 matching lines @@
     EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(799)), secondRow);
     LayoutMultiColumnSet* thirdRow = secondRow->nextSiblingMultiColumnSet();
     EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(800)), thirdRow);
     EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(899)), thirdRow); // bottom of last row
     EXPECT_EQ(flowThread->columnSetAtBlockOffset(LayoutUnit(10000)), thirdRow); // overflow
 }
 
 class MultiColumnTreeModifyingTest : public MultiColumnRenderingTest {
 public:
     void setMulticolHTML(const char*);
-    void reparentLayoutObject(const char* newParentId, const char* childId, const char* insertBeforeId = 0);
+    void reparentLayoutObject(const char* newParentId, const char* childId, const char* insertBeforeId = nullptr);
     void destroyLayoutObject(LayoutObject* child);
     void destroyLayoutObject(const char* childId);
 };
 
 void MultiColumnTreeModifyingTest::setMulticolHTML(const char* html)
 {
     MultiColumnRenderingTest::setMulticolHTML(html);
     // Allow modifications to the layout tree structure, because that's what we want to test.
     document().lifecycle().advanceTo(DocumentLifecycle::InStyleRecalc);
 }
 
 void MultiColumnTreeModifyingTest::reparentLayoutObject(const char* newParentId, const char* childId, const char* insertBeforeId)
 {
     LayoutObject* newParent = document().getElementById(newParentId)->layoutObject();
     LayoutObject* child = document().getElementById(childId)->layoutObject();
-    LayoutObject* insertBefore = insertBeforeId ? document().getElementById(insertBeforeId)->layoutObject() : 0;
+    LayoutObject* insertBefore = insertBeforeId ? document().getElementById(insertBeforeId)->layoutObject() : nullptr;
     child->remove();
     newParent->addChild(child, insertBefore);
 }
 
 void MultiColumnTreeModifyingTest::destroyLayoutObject(LayoutObject* child)
 {
     // Remove and destroy in separate steps, so that we get to test removal of subtrees.
     child->remove();
     child->node()->detach();
 }
@@ skipping 423 matching lines @@
 {
     setMulticolHTML("<div id='mc'>text<div id='spanner'><div class='s'></div></div>text</div>");
     EXPECT_EQ(columnSetSignature("mc"), "csc");
     destroyLayoutObject("spanner");
     EXPECT_EQ(columnSetSignature("mc"), "c");
 }
 
 } // anonymous namespace
 
 } // namespace blink