Allow empty handles to escape handle scopes.

src/api.h

Index: src/api.h
diff --git a/src/api.h b/src/api.h
index 2f1f77cbba5c1cceda98de1bacf718888b0f5e12..7b88112c04dbe699bb6546d11bffb0ed6e5da4bd 100644
--- a/src/api.h
+++ b/src/api.h
@@ -247,7 +247,11 @@ static inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
 template <class T>
 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
     v8::HandleScope* scope) {
-  return Utils::OpenHandle(*scope->Close(Utils::ToLocal(*this)));
+  v8::internal::Handle<T> handle;
+  if (!is_null()) {
+    handle = *this;
+  }
+  return Utils::OpenHandle(*scope->Close(Utils::ToLocal(handle)));
 }
 
 
@@ -255,7 +259,7 @@ v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
 
 #define MAKE_TO_LOCAL(Name, From, To)                                       \
   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
-    ASSERT(!obj->IsTheHole());                                              \
+    ASSERT(obj.is_null() || !obj->IsTheHole());                             \
     return Local<To>(reinterpret_cast<To*>(obj.location()));                \
   }