[api,heap] Fix external GC callbacks.

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 6972 matching lines @@
       v8::internal::Handle<v8::internal::Object>(parent).location();
   internal_isolate->global_handles()->SetReference(
       reinterpret_cast<i::HeapObject**>(parent_location),
       v8::internal::Handle<v8::internal::Object>(child).location());
 }
 
 
 void Isolate::AddGCPrologueCallback(GCPrologueCallback callback,
                                     GCType gc_type) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
-  isolate->heap()->AddGCPrologueCallback(callback, gc_type);
+  GCCallback new_callback = reinterpret_cast<GCCallback>(callback);
+  isolate->heap()->AddGCPrologueCallback(new_callback, gc_type);
 }
 
 
 void Isolate::RemoveGCPrologueCallback(GCPrologueCallback callback) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   isolate->heap()->RemoveGCPrologueCallback(callback);
 }
 
 
 void Isolate::AddGCEpilogueCallback(GCEpilogueCallback callback,
                                     GCType gc_type) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
-  isolate->heap()->AddGCEpilogueCallback(callback, gc_type);
+  GCCallback new_callback = reinterpret_cast<GCCallback>(callback);
+  isolate->heap()->AddGCEpilogueCallback(new_callback, gc_type);
 }
 
 
 void Isolate::RemoveGCEpilogueCallback(GCEpilogueCallback callback) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   isolate->heap()->RemoveGCEpilogueCallback(callback);
 }
 
 
 void V8::AddGCPrologueCallback(GCPrologueCallback callback, GCType gc_type) {
@@ skipping 1397 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