Revert of Move the event attach/detach logic on unload from event.js to

extensions/renderer/object_backed_native_handler.cc

Index: extensions/renderer/object_backed_native_handler.cc
diff --git a/extensions/renderer/object_backed_native_handler.cc b/extensions/renderer/object_backed_native_handler.cc
index 075f1d60173a6925218ccaf4fb7a7f769293a0ca..10bedc1772fb714a604860d20e133ad1e07226d9 100644
--- a/extensions/renderer/object_backed_native_handler.cc
+++ b/extensions/renderer/object_backed_native_handler.cc
@@ -25,8 +25,7 @@
                        v8::ObjectTemplate::New(context->isolate())) {
 }
 
-ObjectBackedNativeHandler::~ObjectBackedNativeHandler() {
-}
+ObjectBackedNativeHandler::~ObjectBackedNativeHandler() { Invalidate(); }
 
 v8::Handle<v8::Object> ObjectBackedNativeHandler::NewInstance() {
   return v8::Local<v8::ObjectTemplate>::New(GetIsolate(), object_template_)
@@ -76,7 +75,9 @@
 }
 
 void ObjectBackedNativeHandler::Invalidate() {
-  v8::Isolate* isolate = GetIsolate();
+  if (!is_valid())
+    return;
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
   v8::HandleScope handle_scope(isolate);
   v8::Context::Scope context_scope(context_->v8_context());
 
@@ -89,10 +90,9 @@
         handler_function_value.As<v8::External>()->Value());
     data->Delete(v8::String::NewFromUtf8(isolate, kHandlerFunction));
   }
-
   router_data_.Clear();
   object_template_.Reset();
-
+  context_ = NULL;
   NativeHandler::Invalidate();
 }