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

Source/core/layout/svg/line/SVGInlineTextBox.cpp

Index: Source/core/layout/svg/line/SVGInlineTextBox.cpp
diff --git a/Source/core/layout/svg/line/SVGInlineTextBox.cpp b/Source/core/layout/svg/line/SVGInlineTextBox.cpp
index e695b086787d4a15d4f55cfa049162fc83f520a3..6efabf9ad885cd20b6fb6e61dcc8c19b245a5236 100644
--- a/Source/core/layout/svg/line/SVGInlineTextBox.cpp
+++ b/Source/core/layout/svg/line/SVGInlineTextBox.cpp
@@ -175,7 +175,7 @@ TextRun SVGInlineTextBox::constructTextRun(const ComputedStyle& style, const SVG
     //                          layout during layout. Remove this when 264211 is fixed.
     RELEASE_ASSERT(!text->needsLayout());
 
-    TextRun run(static_cast<const LChar*>(0) // characters, will be set below if non-zero.
+    TextRun run(static_cast<const LChar*>(nullptr) // characters, will be set below if non-zero.
         , 0 // length, will be set below if non-zero.
         , 0 // xPos, only relevant with allowTabs=true
         , 0 // padding, only relevant for justified text, not relevant for SVG