Reduce boilerplace for common pattern to return MaybeHandle.

src/runtime/runtime-json.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/char-predicates-inl.h"
 #include "src/isolate-inl.h"
 #include "src/json-parser.h"
 #include "src/json-stringifier.h"
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
 
 RUNTIME_FUNCTION(Runtime_QuoteJSONString) {
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
   DCHECK(args.length() == 1);
-  Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result, BasicJsonStringifier::StringifyString(isolate, string));
-  return *result;
+  RETURN_RESULT_OR_FAILURE(
+      isolate, BasicJsonStringifier::StringifyString(isolate, string));
 }
 
 RUNTIME_FUNCTION(Runtime_BasicJSONStringify) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Object, gap, 1);
-  Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result, BasicJsonStringifier(isolate).Stringify(object, gap));
-  return *result;
+  CONVERT_ARG_HANDLE_CHECKED(String, gap, 1);
+  RETURN_RESULT_OR_FAILURE(
+      isolate, BasicJsonStringifier(isolate).Stringify(object, gap));
 }
 
 RUNTIME_FUNCTION(Runtime_ParseJson) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
   Handle<String> source;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, source,
                                      Object::ToString(isolate, object));
   source = String::Flatten(source);
   // Optimized fast case where we only have Latin1 characters.
-  Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result,
-                                     source->IsSeqOneByteString()
-                                         ? JsonParser<true>::Parse(source)
-                                         : JsonParser<false>::Parse(source));
-  return *result;
+  RETURN_RESULT_OR_FAILURE(isolate, source->IsSeqOneByteString()
+                                        ? JsonParser<true>::Parse(source)
+                                        : JsonParser<false>::Parse(source));
 }
 
 }  // namespace internal
 }  // namespace v8