Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/wtf/TypedArrayBase.h

Index: Source/wtf/TypedArrayBase.h
diff --git a/Source/wtf/TypedArrayBase.h b/Source/wtf/TypedArrayBase.h
index 491a3381f9241225dc34081509fd90f2291f934b..6acfc15382eceefe79cb6151d364ea78e453a081 100644
--- a/Source/wtf/TypedArrayBase.h
+++ b/Source/wtf/TypedArrayBase.h
@@ -93,7 +93,7 @@ protected:
     {
         RefPtr<ArrayBuffer> buffer = ArrayBuffer::create(length, sizeof(T));
         if (!buffer.get())
-            return 0;
+            return nullptr;
         return create<Subclass>(buffer, 0, length);
     }
 
@@ -114,7 +114,7 @@ protected:
     {
         RefPtr<ArrayBuffer> buf(buffer);
         if (!verifySubRange<T>(buf, byteOffset, length))
-            return 0;
+            return nullptr;
 
         return adoptRef(new Subclass(buf, byteOffset, length));
     }
@@ -124,7 +124,7 @@ protected:
     {
         RefPtr<ArrayBuffer> buffer = ArrayBuffer::createUninitialized(length, sizeof(T));
         if (!buffer.get())
-            return 0;
+            return nullptr;
         return create<Subclass>(buffer, 0, length);
     }