Re-land rev. 12849 and 12868 (Heavy cleanup of the external pointer API + related fix).

test/cctest/test-decls.cc

 // Copyright 2007-2008 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 172 matching lines @@
 
 v8::Handle<Integer> DeclarationContext::HandleQuery(Local<String> key,
                                                     const AccessorInfo& info) {
   DeclarationContext* context = GetInstance(info);
   context->query_count_++;
   return context->Query(key);
 }
 
 
 DeclarationContext* DeclarationContext::GetInstance(const AccessorInfo& info) {
-  return static_cast<DeclarationContext*>(External::Unwrap(info.Data()));
+  void* value = External::Cast(*info.Data())->Value();
+  return static_cast<DeclarationContext*>(value);
 }
 
 
 v8::Handle<Value> DeclarationContext::Get(Local<String> key) {
   return v8::Handle<Value>();
 }
 
 
 v8::Handle<Value> DeclarationContext::Set(Local<String> key,
                                           Local<Value> value) {
@@ skipping 693 matching lines @@
                   EXPECT_ERROR);
   }
 
   { SimpleContext context;
     context.Check("const x = 1; x",
                   EXPECT_RESULT, Number::New(1));
     context.Check("function x() { return 2 }; x()",
                   EXPECT_ERROR);
   }
 }