Fix ResourceSchedulingFilter crash after ResourceDispatcher deleted

content/child/resource_scheduling_filter.cc

 // Copyright (c) 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 "content/child/resource_scheduling_filter.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "content/child/resource_dispatcher.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_message_start.h"
 
 namespace content {
 
 ResourceSchedulingFilter::ResourceSchedulingFilter(
     const scoped_refptr<base::SingleThreadTaskRunner>& main_thread_task_runner,
     ResourceDispatcher* resource_dispatcher)
     : main_thread_task_runner_(main_thread_task_runner),
-      resource_dispatcher_(resource_dispatcher),
+      resource_dispatcher_(resource_dispatcher->GetWeakPtr()),
       weak_ptr_factory_(this) {
   DCHECK(main_thread_task_runner_.get());
-  DCHECK(resource_dispatcher_);
 }
 
 ResourceSchedulingFilter::~ResourceSchedulingFilter() {
 }
 
 bool ResourceSchedulingFilter::OnMessageReceived(const IPC::Message& message) {
   base::AutoLock lock(request_id_to_task_runner_map_lock_);
   int request_id;
 
   base::PickleIterator pickle_iterator(message);
@@ skipping 29 matching lines @@
   request_id_to_task_runner_map_.erase(id);
 }
 
 bool ResourceSchedulingFilter::GetSupportedMessageClasses(
     std::vector<uint32_t>* supported_message_classes) const {
   supported_message_classes->push_back(ResourceMsgStart);
   return true;
 }
 
 void ResourceSchedulingFilter::DispatchMessage(const IPC::Message& message) {
-  resource_dispatcher_->OnMessageReceived(message);
+  if (resource_dispatcher_)
+    resource_dispatcher_->OnMessageReceived(message);
 }
 
 }  // namespace content