extensions: Destroy ExtensionMessageFilter on IO thread.

extensions/browser/extension_message_filter.cc

 // Copyright 2014 The Chromium 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 "extensions/browser/extension_message_filter.h"
 
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/resource_dispatcher_host.h"
 #include "extensions/browser/blob_holder.h"
@@ skipping 13 matching lines @@
 ExtensionMessageFilter::ExtensionMessageFilter(int render_process_id,
                                                content::BrowserContext* context)
     : BrowserMessageFilter(ExtensionMsgStart),
       render_process_id_(render_process_id),
       browser_context_(context),
       extension_info_map_(ExtensionSystem::Get(context)->info_map()),
       weak_ptr_factory_(this) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 }
 
 ExtensionMessageFilter::~ExtensionMessageFilter() {}

[James Cook, 2014/06/02 19:50:43]

DCHECK_CURRENTLY_ON(BrowserThread::IO)

[Daniel Erat, 2014/06/02 20:07:59]

Done.

 
 void ExtensionMessageFilter::OverrideThreadForMessage(
     const IPC::Message& message,
     BrowserThread::ID* thread) {
   switch (message.type()) {
     case ExtensionHostMsg_AddListener::ID:
     case ExtensionHostMsg_RemoveListener::ID:
     case ExtensionHostMsg_AddLazyListener::ID:
     case ExtensionHostMsg_RemoveLazyListener::ID:
     case ExtensionHostMsg_AddFilteredListener::ID:
     case ExtensionHostMsg_RemoveFilteredListener::ID:
     case ExtensionHostMsg_ShouldSuspendAck::ID:
     case ExtensionHostMsg_SuspendAck::ID:
     case ExtensionHostMsg_TransferBlobsAck::ID:
       *thread = BrowserThread::UI;
       break;
     default:
       break;
   }
 }
 
+void ExtensionMessageFilter::OnDestruct() const {
+  BrowserThread::DeleteOnIOThread::Destruct(this);

[James Cook, 2014/06/02 19:50:43]

I would document either here or in the header why it has to be destroyed on the
IO thread.

Optional alternative: If you think we're slathering this with too many comments
to cover up a code smell, consider splitting into two message filters, one that
just handles IO thread messages.

[Daniel Erat, 2014/06/02 20:07:59]

Done.

(i went with the easy/lazy approach of adding comments)

+}
+
 bool ExtensionMessageFilter::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(ExtensionMessageFilter, message)
     IPC_MESSAGE_HANDLER(ExtensionHostMsg_AddListener,
                         OnExtensionAddListener)
     IPC_MESSAGE_HANDLER(ExtensionHostMsg_RemoveListener,
                         OnExtensionRemoveListener)
     IPC_MESSAGE_HANDLER(ExtensionHostMsg_AddLazyListener,
                         OnExtensionAddLazyListener)
     IPC_MESSAGE_HANDLER(ExtensionHostMsg_RemoveLazyListener,
@@ skipping 130 matching lines @@
   ExtensionFunctionDispatcher::DispatchOnIOThread(
       extension_info_map_.get(),
       browser_context_,
       render_process_id_,
       weak_ptr_factory_.GetWeakPtr(),
       routing_id,
       params);
 }
 
 }  // namespace extensions