Make isolate.h usable without objects-inl.h header.

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);
@@ skipping 26 matching lines @@
   // 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;
 }
 }  // namespace internal
 }  // namespace v8