Abstract string building in JSON-stringifier into IncrementalStringBuilder.

tools/gyp/v8.gyp

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 770 matching lines @@
         '../../src/runtime/runtime-regexp.cc',
         '../../src/runtime/runtime-scopes.cc',
         '../../src/runtime/runtime-strings.cc',
         '../../src/runtime/runtime-symbol.cc',
         '../../src/runtime/runtime-test.cc',
         '../../src/runtime/runtime-typedarray.cc',
         '../../src/runtime/runtime-uri.cc',
         '../../src/runtime/runtime-utils.h',
         '../../src/runtime/runtime.cc',
         '../../src/runtime/runtime.h',
-        '../../src/runtime/string-builder.h',
         '../../src/safepoint-table.cc',
         '../../src/safepoint-table.h',
         '../../src/sampler.cc',
         '../../src/sampler.h',
         '../../src/scanner-character-streams.cc',
         '../../src/scanner-character-streams.h',
         '../../src/scanner.cc',
         '../../src/scanner.h',
         '../../src/scopeinfo.cc',
         '../../src/scopeinfo.h',
         '../../src/scopes.cc',
         '../../src/scopes.h',
         '../../src/serialize.cc',
         '../../src/serialize.h',
         '../../src/small-pointer-list.h',
         '../../src/smart-pointers.h',
         '../../src/snapshot.h',
         '../../src/snapshot-source-sink.cc',
         '../../src/snapshot-source-sink.h',
+        '../../src/string-builder.h',
+        '../../src/string-builder.cc',
         '../../src/string-search.cc',
         '../../src/string-search.h',
         '../../src/string-stream.cc',
         '../../src/string-stream.h',
         '../../src/strtod.cc',
         '../../src/strtod.h',
         '../../src/ic/stub-cache.cc',
         '../../src/ic/stub-cache.h',
         '../../src/token.cc',
         '../../src/token.h',
@@ skipping 917 matching lines @@
         }],
         ['v8_compress_startup_data=="bz2"', {
           'libraries': [
             '-lbz2',
           ]
         }],
       ],
     },
   ],
 }