IPC: Make ChannelReader inherit from SupportsAttachmentBrokering.

ipc/ipc_sync_channel.cc

Index: ipc/ipc_sync_channel.cc
diff --git a/ipc/ipc_sync_channel.cc b/ipc/ipc_sync_channel.cc
index 06cd46f1ea60aece2a1d630bd2cdf4ec3550dc68..35b88a7edeb43a64ea0b37cf91b284c1ca0f8596 100644
--- a/ipc/ipc_sync_channel.cc
+++ b/ipc/ipc_sync_channel.cc
@@ -412,10 +412,11 @@ scoped_ptr<SyncChannel> SyncChannel::Create(
     Listener* listener,
     const scoped_refptr<base::SingleThreadTaskRunner>& ipc_task_runner,
     bool create_pipe_now,
-    base::WaitableEvent* shutdown_event) {
+    base::WaitableEvent* shutdown_event,
+    AttachmentBroker* broker) {
   scoped_ptr<SyncChannel> channel =
       Create(listener, ipc_task_runner, shutdown_event);
-  channel->Init(channel_handle, mode, create_pipe_now);
+  channel->Init(channel_handle, mode, create_pipe_now, broker);
   return channel.Pass();
 }