Turn //mojo/public/cpp/bindings and //mojo/public/cpp/system into components

mojo/public/cpp/system/watcher.h

 // Copyright 2016 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_PUBLIC_CPP_SYSTEM_WATCHER_H_
 #define MOJO_PUBLIC_CPP_SYSTEM_WATCHER_H_
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_checker.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "mojo/public/c/system/types.h"
 #include "mojo/public/cpp/system/handle.h"
+#include "mojo/public/cpp/system/system_export.h"
 
 namespace mojo {
 
 // A Watcher watches a single Mojo handle for signal state changes.
 //
 // NOTE: Watchers may only be used on threads which have a running MessageLoop.
-class Watcher {
+class MOJO_CPP_SYSTEM_EXPORT Watcher {
  public:
   // A callback to be called any time a watched handle changes state in some
   // interesting way. The |result| argument indicates one of the following
   // conditions depending on its value:
   //
   //   |MOJO_RESULT_OK|: One or more of the signals being watched is satisfied.
   //
   //   |MOJO_RESULT_FAILED_PRECONDITION|: None of the signals being watched can
   //       ever be satisfied again.
   //
@@ skipping 80 matching lines @@
   ReadyCallback callback_;
 
   base::WeakPtrFactory<Watcher> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Watcher);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_SYSTEM_WATCHER_H_