Revert of Mojo: Armed Watchers

mojo/common/data_pipe_drainer.h

 // Copyright 2014 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_COMMON_DATA_PIPE_DRAINER_H_
 #define MOJO_COMMON_DATA_PIPE_DRAINER_H_
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "mojo/common/mojo_common_export.h"
 #include "mojo/public/cpp/system/core.h"
-#include "mojo/public/cpp/system/simple_watcher.h"
+#include "mojo/public/cpp/system/watcher.h"
 
 namespace mojo {
 namespace common {
 
 class MOJO_COMMON_EXPORT DataPipeDrainer {
  public:
   class Client {
    public:
     virtual void OnDataAvailable(const void* data, size_t num_bytes) = 0;
     virtual void OnDataComplete() = 0;
 
    protected:
     virtual ~Client() {}
   };
 
   DataPipeDrainer(Client*, mojo::ScopedDataPipeConsumerHandle source);
   ~DataPipeDrainer();
 
  private:
   void ReadData();
   void WaitComplete(MojoResult result);
 
   Client* client_;
   mojo::ScopedDataPipeConsumerHandle source_;
-  mojo::SimpleWatcher handle_watcher_;
+  mojo::Watcher handle_watcher_;
 
   base::WeakPtrFactory<DataPipeDrainer> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DataPipeDrainer);
 };
 
 }  // namespace common
 }  // namespace mojo
 
 #endif  // MOJO_COMMON_DATA_PIPE_DRAINER_H_