Reland #1: Clean up interface of attachment broker.

ipc/ipc_channel_reader.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_reader.h"
 
 #include <algorithm>
 
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_logging.h"
@@ skipping 145 matching lines @@
   std::string name;
   Logging::GetInstance()->GetMessageText(m->type(), &name, m, NULL);
   TRACE_EVENT1("ipc,toplevel", "ChannelReader::DispatchInputData", "name",
                name);
 #else
   TRACE_EVENT2("ipc,toplevel", "ChannelReader::DispatchInputData", "class",
                IPC_MESSAGE_ID_CLASS(m->type()), "line",
                IPC_MESSAGE_ID_LINE(m->type()));
 #endif
   m->TraceMessageEnd();
-  if (IsInternalMessage(*m))
+
+  bool handled = false;
+  if (IsInternalMessage(*m)) {
     HandleInternalMessage(*m);
-  else
+    handled = true;
+  }
+#if USE_ATTACHMENT_BROKER
+  if (!handled && IsAttachmentBrokerEndpoint() && GetAttachmentBroker()) {
+    handled = GetAttachmentBroker()->OnMessageReceived(*m);
+  }
+#endif  // USE_ATTACHMENT_BROKER
+  if (!handled)
     listener_->OnMessageReceived(*m);
   if (m->dispatch_error())
     listener_->OnBadMessageReceived(*m);
 }
 
 ChannelReader::AttachmentIdSet ChannelReader::GetBrokeredAttachments(
     Message* msg) {
   std::set<BrokerableAttachment::AttachmentId> blocked_ids;
 
 #if USE_ATTACHMENT_BROKER
@@ skipping 40 matching lines @@
 }
 
 void ChannelReader::StopObservingAttachmentBroker() {
 #if USE_ATTACHMENT_BROKER
   GetAttachmentBroker()->RemoveObserver(this);
 #endif  // USE_ATTACHMENT_BROKER
 }
 
 }  // namespace internal
 }  // namespace IPC