[heap] Cleanup string factory methods a bit.

src/runtime/runtime-strings.cc

Index: src/runtime/runtime-strings.cc
diff --git a/src/runtime/runtime-strings.cc b/src/runtime/runtime-strings.cc
index b8ccbc8d93a98b5d1935c35d73165b07082b00b4..3ce5a58e2bfbc340651abf7258ab760257723785 100644
--- a/src/runtime/runtime-strings.cc
+++ b/src/runtime/runtime-strings.cc
@@ -1158,28 +1158,6 @@ RUNTIME_FUNCTION(Runtime_NewString) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_NewConsString) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 4);
-  CONVERT_INT32_ARG_CHECKED(length, 0);
-  CONVERT_BOOLEAN_ARG_CHECKED(is_one_byte, 1);
-  CONVERT_ARG_HANDLE_CHECKED(String, left, 2);
-  CONVERT_ARG_HANDLE_CHECKED(String, right, 3);
-
-  Handle<String> result;
-  if (is_one_byte) {
-    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-        isolate, result,
-        isolate->factory()->NewOneByteConsString(length, left, right));
-  } else {
-    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-        isolate, result,
-        isolate->factory()->NewTwoByteConsString(length, left, right));
-  }
-  return *result;
-}
-
-
 RUNTIME_FUNCTION(Runtime_StringEquals) {
   HandleScope handle_scope(isolate);
   DCHECK(args.length() == 2);