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

Source/core/layout/svg/SVGTextQuery.cpp

Index: Source/core/layout/svg/SVGTextQuery.cpp
diff --git a/Source/core/layout/svg/SVGTextQuery.cpp b/Source/core/layout/svg/SVGTextQuery.cpp
index 93af79aa2505d8a42cf2f5f27a6f5fe0571b6026..2a0ef770c6bf40fe76e7c888abf3ca9aa33dea6a 100644
--- a/Source/core/layout/svg/SVGTextQuery.cpp
+++ b/Source/core/layout/svg/SVGTextQuery.cpp
@@ -38,8 +38,8 @@ struct QueryData {
     QueryData()
         : isVerticalText(false)
         , currentOffset(0)
-        , textLayoutObject(0)
-        , textBox(0)
+        , textLayoutObject(nullptr)
+        , textBox(nullptr)
     {
     }
 
@@ -52,7 +52,7 @@ struct QueryData {
 static inline InlineFlowBox* flowBoxForLayoutObject(LayoutObject* layoutObject)
 {
     if (!layoutObject)
-        return 0;
+        return nullptr;
 
     if (layoutObject->isLayoutBlock()) {
         // If we're given a block element, it has to be a LayoutSVGText.
@@ -76,7 +76,7 @@ static inline InlineFlowBox* flowBoxForLayoutObject(LayoutObject* layoutObject)
     }
 
     ASSERT_NOT_REACHED();
-    return 0;
+    return nullptr;
 }
 
 static void collectTextBoxesInFlowBox(InlineFlowBox* flowBox, Vector<SVGInlineTextBox*>& textBoxes)