Revert of Remove dependency on content from remoting_host.

remoting/host/chromeos/clipboard_aura.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 REMOTING_HOST_CLIPBOARD_AURA_H_
 #define REMOTING_HOST_CLIPBOARD_AURA_H_
 
 #include "base/memory/scoped_ptr.h"
-#include "base/threading/thread_checker.h"
-#include "base/timer/timer.h"
+#include "base/single_thread_task_runner.h"
 #include "remoting/host/clipboard.h"
 
 namespace remoting {
 
 namespace protocol {
 class ClipboardStub;
 }  // namespace protocol
 
 // On Chrome OS, the clipboard is managed by aura instead of the underlying
 // native platform (e.g. x11, ozone, etc).
 //
 // This class (1) monitors the aura clipboard for changes and notifies the
 // |client_clipboard|, and (2) provides an interface to inject clipboard event
 // into aura.
 //
 // The public API of this class can be called in any thread as internally it
 // always posts the call to the |ui_task_runner|.  On ChromeOS, that should
 // be the UI thread of the browser process.
+//
 class ClipboardAura : public Clipboard {
  public:
-  explicit ClipboardAura();
+  explicit ClipboardAura(
+      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
   ~ClipboardAura() override;
 
   // Clipboard interface.
   void Start(scoped_ptr<protocol::ClipboardStub> client_clipboard) override;
   void InjectClipboardEvent(const protocol::ClipboardEvent& event) override;
   void Stop() override;
 
   // Overrides the clipboard polling interval for unit test.
   void SetPollingIntervalForTesting(base::TimeDelta polling_interval);
 
  private:
-  void CheckClipboardForChanges();
+  class Core;
 
-  base::ThreadChecker thread_checker_;
-  scoped_ptr<protocol::ClipboardStub> client_clipboard_;
-  base::RepeatingTimer<ClipboardAura> clipboard_polling_timer_;
-  uint64 current_change_count_;
-  base::TimeDelta polling_interval_;
+  scoped_ptr<Core> core_;
+  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(ClipboardAura);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_CLIPBOARD_AURA_H_