[remoting android] Remove host It2Me implementation.

remoting/host/disconnect_window_android.cc

-// 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.
-
-#include "base/logging.h"
-#include "base/macros.h"
-#include "base/memory/ptr_util.h"
-#include "remoting/host/host_window.h"
-
-namespace remoting {
-
-namespace {
-
-class DisconnectWindowAndroid : public HostWindow {
- public:
-  DisconnectWindowAndroid() {}
-
-  // HostWindow interface.
-  void Start(const base::WeakPtr<ClientSessionControl>& client_session_control)
-      override {
-    NOTIMPLEMENTED();
-  }
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(DisconnectWindowAndroid);
-};
-
-}  // namespace
-
-// static
-std::unique_ptr<HostWindow> HostWindow::CreateDisconnectWindow() {
-  return base::MakeUnique<DisconnectWindowAndroid>();
-}
-
-}  // namespace remoting