[json parser] add position to error message.

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 911 matching lines @@
         '../../src/interpreter/handler-table-builder.h',
         '../../src/interpreter/interpreter.cc',
         '../../src/interpreter/interpreter.h',
         '../../src/interpreter/register-translator.cc',
         '../../src/interpreter/register-translator.h',
         '../../src/interpreter/source-position-table.cc',
         '../../src/interpreter/source-position-table.h',
         '../../src/isolate-inl.h',
         '../../src/isolate.cc',
         '../../src/isolate.h',
+        '../../src/json-parser.h',
         '../../src/json-stringifier.h',
         '../../src/key-accumulator.h',
         '../../src/key-accumulator.cc',
         '../../src/layout-descriptor-inl.h',
         '../../src/layout-descriptor.cc',
         '../../src/layout-descriptor.h',
         '../../src/list-inl.h',
         '../../src/list.h',
         '../../src/locked-queue-inl.h',
         '../../src/locked-queue.h',
@@ skipping 17 matching lines @@
         '../../src/objects-printer.cc',
         '../../src/objects.cc',
         '../../src/objects.h',
         '../../src/optimizing-compile-dispatcher.cc',
         '../../src/optimizing-compile-dispatcher.h',
         '../../src/ostreams.cc',
         '../../src/ostreams.h',
         '../../src/parsing/expression-classifier.h',
         '../../src/parsing/func-name-inferrer.cc',
         '../../src/parsing/func-name-inferrer.h',
-        '../../src/parsing/json-parser.h',
         '../../src/parsing/parameter-initializer-rewriter.cc',
         '../../src/parsing/parameter-initializer-rewriter.h',
         '../../src/parsing/parser-base.h',
         '../../src/parsing/parser.cc',
         '../../src/parsing/parser.h',
         '../../src/parsing/pattern-rewriter.cc',
         '../../src/parsing/preparse-data-format.h',
         '../../src/parsing/preparse-data.cc',
         '../../src/parsing/preparse-data.h',
         '../../src/parsing/preparser.cc',
@@ skipping 1202 matching lines @@
         }],
         ['want_separate_host_toolset==1', {
           'toolsets': ['host'],
         }, {
           'toolsets': ['target'],
         }],
       ],
     },
   ],
 }