Use macros instead of specializing VectorTraits explicitly

Source/wtf/text/WTFString.h

Index: Source/wtf/text/WTFString.h
diff --git a/Source/wtf/text/WTFString.h b/Source/wtf/text/WTFString.h
index bf39ad20ef8fe685da931137b54d998a544ef4a1..c1098672a815a30ca765013d56b1aca2fa193ee6 100644
--- a/Source/wtf/text/WTFString.h
+++ b/Source/wtf/text/WTFString.h
@@ -664,10 +664,6 @@ template<> struct DefaultHash<String> {
     typedef StringHash Hash;
 };
 
-template <> struct VectorTraits<String> : SimpleClassVectorTraits<String> {
-    static const bool canCompareWithMemcmp = false;
-};
-
 // Shared global empty string.
 WTF_EXPORT const String& emptyString();
 
@@ -679,6 +675,8 @@ WTF_EXPORT extern const String xmlnsWithColon;
 
 } // namespace WTF
 
+WTF_ALLOW_MOVE_AND_INIT_WITH_MEM_FUNCTIONS(String);
+
 using WTF::CString;
 using WTF::KeepTrailingZeros;
 using WTF::StrictUTF8Conversion;