Abstract string building in JSON-stringifier into IncrementalStringBuilder.

src/runtime/runtime-strings.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/v8.h"
 
 #include "src/arguments.h"
 #include "src/jsregexp-inl.h"
 #include "src/jsregexp.h"
 #include "src/runtime/runtime-utils.h"
-#include "src/runtime/string-builder.h"
+#include "src/string-builder.h"
 #include "src/string-search.h"
 
 namespace v8 {
 namespace internal {
 
 
 // Perform string match of pattern on subject, starting at start index.
 // Caller must ensure that 0 <= start_index <= sub->length(),
 // and should check that pat->length() + start_index <= sub->length().
 int StringMatch(Isolate* isolate, Handle<String> sub, Handle<String> pat,
@@ skipping 1274 matching lines @@
   return __RT_impl_Runtime_StringAdd(args, isolate);
 }
 
 
 RUNTIME_FUNCTION(RuntimeReference_IsStringWrapperSafeForDefaultValueOf) {
   UNIMPLEMENTED();
   return NULL;
 }
 }
 }  // namespace v8::internal