[mojo-edk] Add MojoWatch and MojoCancelWatch APIs

mojo/edk/system/data_pipe_producer_dispatcher.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_DATA_PIPE_PRODUCER_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_DATA_PIPE_PRODUCER_DISPATCHER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 24 matching lines @@
       NodeController* node_controller,
       const ports::PortRef& port,
       scoped_refptr<PlatformSharedBuffer> shared_ring_buffer,
       const MojoCreateDataPipeOptions& options,
       bool initialized,
       uint64_t pipe_id);
 
   // Dispatcher:
   Type GetType() const override;
   MojoResult Close() override;
+  MojoResult Watch(MojoHandleSignals signals,
+                   const Watcher::WatchCallback& callback,
+                   uintptr_t context) override;
+  MojoResult CancelWatch(uintptr_t context) override;
   MojoResult WriteData(const void* elements,
                        uint32_t* num_bytes,
                        MojoReadDataFlags flags) override;
   MojoResult BeginWriteData(void** buffer,
                             uint32_t* buffer_num_bytes,
                             MojoWriteDataFlags flags) override;
   MojoResult EndWriteData(uint32_t num_bytes_written) override;
   HandleSignalsState GetHandleSignalsState() const override;
   MojoResult AddAwakable(Awakable* awakable,
                          MojoHandleSignals signals,
@@ skipping 60 matching lines @@
   uint32_t write_offset_ = 0;
   uint32_t available_capacity_;
 
   DISALLOW_COPY_AND_ASSIGN(DataPipeProducerDispatcher);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_DATA_PIPE_PRODUCER_DISPATCHER_H_