Add different behavior to AwakableList for "persistent" vs "one-shot" awakables.

mojo/edk/system/message_pipe.h

 // 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.
 
 #ifndef MOJO_EDK_SYSTEM_MESSAGE_PIPE_H_
 #define MOJO_EDK_SYSTEM_MESSAGE_PIPE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 84 matching lines @@
   MojoResult ReadMessage(unsigned port,
                          UserPointer<void> bytes,
                          UserPointer<uint32_t> num_bytes,
                          HandleVector* handles,
                          uint32_t* num_handles,
                          MojoReadMessageFlags flags);
   HandleSignalsState GetHandleSignalsState(unsigned port) const;
   MojoResult AddAwakable(unsigned port,
                          Awakable* awakable,
                          uint64_t context,
-                         bool force,
+                         bool persistent,
                          MojoHandleSignals signals,
                          HandleSignalsState* signals_state);
   void RemoveAwakable(unsigned port,
                       bool match_context,
                       Awakable* awakable,
                       uint64_t context,
                       HandleSignalsState* signals_state);
   void StartSerialize(unsigned port,
                       Channel* channel,
                       size_t* max_size,
@@ skipping 36 matching lines @@
   mutable util::Mutex mutex_;
   std::unique_ptr<MessagePipeEndpoint> endpoints_[2] MOJO_GUARDED_BY(mutex_);
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(MessagePipe);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_MESSAGE_PIPE_H_