Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/rendering/AbstractInlineTextBox.cpp

Index: Source/core/rendering/AbstractInlineTextBox.cpp
diff --git a/Source/core/rendering/AbstractInlineTextBox.cpp b/Source/core/rendering/AbstractInlineTextBox.cpp
index a14b4a0e876f06e769c21c00b89d97a6caea05e8..6598e576154ea542cb017126ffd1fe263b9e1d00 100644
--- a/Source/core/rendering/AbstractInlineTextBox.cpp
+++ b/Source/core/rendering/AbstractInlineTextBox.cpp
@@ -41,7 +41,7 @@ AbstractInlineTextBox::InlineToAbstractInlineTextBoxHashMap* AbstractInlineTextB
 PassRefPtr<AbstractInlineTextBox> AbstractInlineTextBox::getOrCreate(RenderText* renderText, InlineTextBox* inlineTextBox)
 {
     if (!inlineTextBox)
-        return 0;
+        return nullptr;
 
     if (!gAbstractInlineTextBoxMap)
         gAbstractInlineTextBoxMap = new InlineToAbstractInlineTextBoxHashMap();
@@ -76,7 +76,7 @@ void AbstractInlineTextBox::detach()
 PassRefPtr<AbstractInlineTextBox> AbstractInlineTextBox::nextInlineTextBox() const
 {
     if (!m_inlineTextBox)
-        return 0;
+        return nullptr;
 
     return getOrCreate(m_renderText, m_inlineTextBox->nextTextBox());
 }