Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/platform/fonts/SimpleFontData.h

Index: Source/platform/fonts/SimpleFontData.h
diff --git a/Source/platform/fonts/SimpleFontData.h b/Source/platform/fonts/SimpleFontData.h
index 525a94818c94a68d6aeeb312587b92d7d9ce5575..e43a2b0ad68fb72b6d4476cd05f6029ce6db7638 100644
--- a/Source/platform/fonts/SimpleFontData.h
+++ b/Source/platform/fonts/SimpleFontData.h
@@ -57,7 +57,7 @@ enum Pitch { UnknownPitch, FixedPitch, VariablePitch };
 class PLATFORM_EXPORT SimpleFontData : public FontData {
 public:
     // Used to create platform fonts.
-    static PassRefPtr<SimpleFontData> create(const FontPlatformData& platformData, PassRefPtr<CustomFontData> customData = 0, bool isTextOrientationFallback = false)
+    static PassRefPtr<SimpleFontData> create(const FontPlatformData& platformData, PassRefPtr<CustomFontData> customData = nullptr, bool isTextOrientationFallback = false)
     {
         return adoptRef(new SimpleFontData(platformData, customData, isTextOrientationFallback));
     }