Rename 'ScalarValueString' to 'USVString' to match Web IDL

Source/core/testing/TypeConversions.idl

Index: Source/core/testing/TypeConversions.idl
diff --git a/Source/core/testing/TypeConversions.idl b/Source/core/testing/TypeConversions.idl
index ba3e99a8974611bbbc734195a1bd60fc2575f13f..fbe1673dced27740e433f969b7bbdfea6daf8c85 100644
--- a/Source/core/testing/TypeConversions.idl
+++ b/Source/core/testing/TypeConversions.idl
@@ -54,11 +54,11 @@
     void setTestByteString(ByteString byteString);
     [ImplementedAs=setTestByteString] void setTestByteStringDefaultNull(optional ByteString byteString = null);
 
-    attribute ScalarValueString testScalarValueString;
-    [ImplementedAs=testScalarValueString, TreatReturnedNullStringAs=Null] attribute ScalarValueString testScalarValueStringTreatReturnedNullStringAsNullAttribute;
-    [ImplementedAs=testScalarValueString, TreatReturnedNullStringAs=Undefined] attribute ScalarValueString testScalarValueStringTreatReturnedNullStringAsUndefinedAttribute;
-    [ImplementedAs=testScalarValueString] ScalarValueString? getTestScalarValueStringTreatReturnedNullStringAsNullMethod();
-    [ImplementedAs=testScalarValueString, TreatReturnedNullStringAs=Undefined] ScalarValueString getTestScalarValueStringTreatReturnedNullStringAsUndefinedMethod();
-    void setTestScalarValueString(ScalarValueString scalarValueString);
-    [ImplementedAs=setTestScalarValueString] void setTestScalarValueStringDefaultNull(optional ScalarValueString scalarValueString = null);
+    attribute USVString testUSVString;
+    [ImplementedAs=testUSVString, TreatReturnedNullStringAs=Null] attribute USVString testUSVStringTreatReturnedNullStringAsNullAttribute;
+    [ImplementedAs=testUSVString, TreatReturnedNullStringAs=Undefined] attribute USVString testUSVStringTreatReturnedNullStringAsUndefinedAttribute;
+    [ImplementedAs=testUSVString] USVString? getTestUSVStringTreatReturnedNullStringAsNullMethod();
+    [ImplementedAs=testUSVString, TreatReturnedNullStringAs=Undefined] USVString getTestUSVStringTreatReturnedNullStringAsUndefinedMethod();
+    void setTestUSVString(USVString usvString);
+    [ImplementedAs=setTestUSVString] void setTestUSVStringDefaultNull(optional USVString usvString = null);
 };