[serializer] small fixes for blink snapshot.

src/api.cc

 // Copyright 2012 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.
 
 #include "src/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 1222 matching lines @@
     }
   }
   return Local<FunctionTemplate>();
 }
 
 Local<FunctionTemplate> FunctionTemplate::NewWithFastHandler(
     Isolate* isolate, FunctionCallback callback,
     experimental::FastAccessorBuilder* fast_handler, v8::Local<Value> data,
     v8::Local<Signature> signature, int length) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  DCHECK(!i_isolate->serializer_enabled());
   LOG_API(i_isolate, FunctionTemplate, NewWithFastHandler);
   ENTER_V8(i_isolate);
   return FunctionTemplateNew(i_isolate, callback, fast_handler, data, signature,
                              length, false);
 }
 
 Local<FunctionTemplate> FunctionTemplate::NewWithCache(
     Isolate* isolate, FunctionCallback callback, Local<Private> cache_property,
     Local<Value> data, Local<Signature> signature, int length) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  DCHECK(!i_isolate->serializer_enabled());
   LOG_API(i_isolate, FunctionTemplate, NewWithFastHandler);
   ENTER_V8(i_isolate);
   return FunctionTemplateNew(i_isolate, callback, nullptr, data, signature,
                              length, false, cache_property);
 }
 
 Local<Signature> Signature::New(Isolate* isolate,
                                 Local<FunctionTemplate> receiver) {
   return Utils::SignatureToLocal(Utils::OpenHandle(*receiver));
 }
@@ skipping 8510 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8