Make it possible to remove an Awakable with a specific "context" from a Dispatcher.

mojo/edk/system/message_pipe_endpoint.cc

 // Copyright 2013 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 "mojo/edk/system/message_pipe_endpoint.h"
 
 #include "base/logging.h"
 
 namespace mojo {
 namespace system {
@@ skipping 27 matching lines @@
   return MOJO_RESULT_INTERNAL;
 }
 
 void MessagePipeEndpoint::RemoveAwakable(Awakable* /*awakable*/,
                                          HandleSignalsState* signals_state) {
   NOTREACHED();
   if (signals_state)
     *signals_state = HandleSignalsState();
 }
 
+void MessagePipeEndpoint::RemoveAwakableWithContext(
+    Awakable* /*awakable*/,
+    uint64_t /*context*/,
+    HandleSignalsState* signals_state) {
+  NOTREACHED();
+  if (signals_state)
+    *signals_state = HandleSignalsState();
+}
+
 void MessagePipeEndpoint::Attach(ChannelEndpoint* /*channel_endpoint*/) {
   NOTREACHED();
 }
 
 }  // namespace system
 }  // namespace mojo