[json parser] add position to error message.

src/messages.h

 // Copyright 2006-2008 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.
 
 // The infrastructure used for (localized) message reporting in V8.
 //
 // Note: there's a big unresolved issue about ownership of the data
 // structures used by this framework.
 
 #ifndef V8_MESSAGES_H_
@@ skipping 388 matching lines @@
   T(InvalidEscapedReservedWord, "Keyword must not contain escaped characters") \
   T(InvalidLhsInAssignment, "Invalid left-hand side in assignment")            \
   T(InvalidCoverInitializedName, "Invalid shorthand property initializer")     \
   T(InvalidDestructuringTarget, "Invalid destructuring assignment target")     \
   T(InvalidLhsInFor, "Invalid left-hand side in for-loop")                     \
   T(InvalidLhsInPostfixOp,                                                     \
     "Invalid left-hand side expression in postfix operation")                  \
   T(InvalidLhsInPrefixOp,                                                      \
     "Invalid left-hand side expression in prefix operation")                   \
   T(InvalidRegExpFlags, "Invalid flags supplied to RegExp constructor '%'")    \
+  T(JsonParseUnexpectedEOS, "Unexpected end of JSON input")                    \
+  T(JsonParseUnexpectedToken, "Unexpected token % in JSON at position %")      \
+  T(JsonParseUnexpectedTokenNumber, "Unexpected number in JSON at position %") \
+  T(JsonParseUnexpectedTokenString, "Unexpected string in JSON at position %") \
   T(LabelRedeclaration, "Label '%' has already been declared")                 \
   T(MalformedArrowFunParamList, "Malformed arrow function parameter list")     \
   T(MalformedRegExp, "Invalid regular expression: /%/: %")                     \
   T(MalformedRegExpFlags, "Invalid regular expression flags")                  \
   T(ModuleExportUndefined, "Export '%' is not defined in module")              \
   T(MultipleDefaultsInSwitch,                                                  \
     "More than one default clause in switch statement")                        \
   T(NewlineAfterThrow, "Illegal newline after throw")                          \
   T(NoCatchOrFinally, "Missing catch or finally after try")                    \
   T(NotIsvar, "builtin %%IS_VAR: not a variable")                              \
@@ skipping 140 matching lines @@
   static Handle<String> GetMessage(Isolate* isolate, Handle<Object> data);
   static base::SmartArrayPointer<char> GetLocalizedMessage(Isolate* isolate,
                                                            Handle<Object> data);
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_MESSAGES_H_