[es6] Implement for-of iterator finalization

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 276 matching lines @@
   T(RegExpNonObject, "% getter called on non-object %")                        \
   T(RegExpNonRegExp, "% getter called on non-RegExp object")                   \
   T(ReinitializeIntl, "Trying to re-initialize % object.")                     \
   T(ResolvedOptionsCalledOnNonObject,                                          \
     "resolvedOptions method called on a non-object or on a object that is "    \
     "not Intl.%.")                                                             \
   T(ResolverNotAFunction, "Promise resolver % is not a function")              \
   T(RestrictedFunctionProperties,                                              \
     "'caller' and 'arguments' are restricted function properties and cannot "  \
     "be accessed in this context.")                                            \
+  T(ReturnMethodNotCallable, "The iterator's 'return' method is not callable") \
   T(StaticPrototype, "Classes may not have static property named prototype")   \
   T(StrictCannotAssign, "Cannot assign to read only '%' in strict mode")       \
   T(StrictDeleteProperty, "Cannot delete property '%' of %")                   \
   T(StrictPoisonPill,                                                          \
     "'caller', 'callee', and 'arguments' properties may not be accessed on "   \
     "strict mode functions or the arguments objects for calls to them")        \
   T(StrictReadOnlyProperty,                                                    \
     "Cannot assign to read only property '%' of % '%'")                        \
   T(StrictCannotCreateProperty, "Cannot create property '%' on % '%'")         \
   T(StrongArity,                                                               \
@@ skipping 256 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_