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

mojo/edk/system/data_pipe_consumer_dispatcher.cc

Index: mojo/edk/system/data_pipe_consumer_dispatcher.cc
diff --git a/mojo/edk/system/data_pipe_consumer_dispatcher.cc b/mojo/edk/system/data_pipe_consumer_dispatcher.cc
index f9c8dc1b016be91a0d7e8ad03a4a0d15c4d440b9..eb93a0452bbd0e89d654e6e5ad29842125954c74 100644
--- a/mojo/edk/system/data_pipe_consumer_dispatcher.cc
+++ b/mojo/edk/system/data_pipe_consumer_dispatcher.cc
@@ -210,6 +210,15 @@ void DataPipeConsumerDispatcher::RemoveAwakableImplNoLock(
   data_pipe_->ConsumerRemoveAwakable(awakable, signals_state);
 }
 
+void DataPipeConsumerDispatcher::RemoveAwakableWithContextImplNoLock(
+    Awakable* awakable,
+    uint64_t context,
+    HandleSignalsState* signals_state) {
+  mutex().AssertHeld();
+  data_pipe_->ConsumerRemoveAwakableWithContext(awakable, context,
+                                                signals_state);
+}
+
 void DataPipeConsumerDispatcher::StartSerializeImplNoLock(
     Channel* channel,
     size_t* max_size,