[remoting android] Remove host It2Me implementation.

remoting/host/curtain_mode_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/curtain_mode.h"
-
-namespace remoting {
-
-namespace {
-
-class CurtainModeAndroid : public CurtainMode {
- public:
-  CurtainModeAndroid() {}
-
-  // Overriden from CurtainMode.
-  bool Activate() override {
-    NOTIMPLEMENTED();
-    return false;
-  }
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(CurtainModeAndroid);
-};
-
-}  // namespace
-
-// static
-std::unique_ptr<CurtainMode> CurtainMode::Create(
-    scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
-    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
-    base::WeakPtr<ClientSessionControl> client_session_control) {
-  return base::WrapUnique(new CurtainModeAndroid());
-}
-
-}  // namespace remoting