Fix data race in IPC::ChannelProxy

ipc/ipc_channel_proxy.cc

 // Copyright (c) 2012 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 "ipc/ipc_channel_proxy.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 306 matching lines @@
   if (logger->Enabled())
     logger->OnPostDispatchMessage(message, channel_id_);
 #endif
 }
 
 // Called on the listener's thread
 void ChannelProxy::Context::OnDispatchConnected() {
   if (channel_connected_called_)
     return;
 
-  if (channel_) {
-    Channel::AssociatedInterfaceSupport* associated_interface_support =
-        channel_->GetAssociatedInterfaceSupport();
-    if (associated_interface_support) {
-      channel_associated_group_.reset(new mojo::AssociatedGroup(
-          *associated_interface_support->GetAssociatedGroup()));
+  {
+    base::AutoLock l(channel_lifetime_lock_);
+    if (channel_) {
+      Channel::AssociatedInterfaceSupport* associated_interface_support =
+          channel_->GetAssociatedInterfaceSupport();
+      if (associated_interface_support) {
+        channel_associated_group_.reset(new mojo::AssociatedGroup(
+            *associated_interface_support->GetAssociatedGroup()));
+      }
     }
   }
 
   channel_connected_called_ = true;
   if (listener_)
     listener_->OnChannelConnected(peer_pid_);
 }
 
 // Called on the listener's thread
 void ChannelProxy::Context::OnDispatchError() {
@@ skipping 250 matching lines @@
   return channel->TakeClientFileDescriptor();
 }
 #endif
 
 void ChannelProxy::OnChannelInit() {
 }
 
 //-----------------------------------------------------------------------------
 
 }  // namespace IPC