Update contents to use attachment broker.

content/child/child_thread_impl.h

Index: content/child/child_thread_impl.h
diff --git a/content/child/child_thread_impl.h b/content/child/child_thread_impl.h
index f32ade7f046045194b764a683608095f5bcd4852..e1fe4fe1f34302e9a03a07dc5dfb3ba14aea3b9c 100644
--- a/content/child/child_thread_impl.h
+++ b/content/child/child_thread_impl.h
@@ -29,7 +29,7 @@ class TraceMemoryController;
 }  // namespace base
 
 namespace IPC {
-class AttachmentBroker;
+class AttachmentBrokerUnprivileged;
 class MessageFilter;
 class ScopedIPCSupport;
 class SyncChannel;
@@ -239,8 +239,8 @@ class CONTENT_EXPORT ChildThreadImpl
   scoped_ptr<MojoApplication> mojo_application_;
 
   std::string channel_name_;
+  scoped_ptr<IPC::AttachmentBrokerUnprivileged> attachment_broker_;
   scoped_ptr<IPC::SyncChannel> channel_;
-  scoped_ptr<IPC::AttachmentBroker> attachment_broker_;
 
   // Allows threads other than the main thread to send sync messages.
   scoped_refptr<IPC::SyncMessageFilter> sync_message_filter_;