[remoting android] Remove host It2Me implementation.

remoting/host/continue_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/continue_window.h"
-
-namespace remoting {
-
-namespace {
-
-class ContinueWindowAndroid : public ContinueWindow {
- public:
-  ContinueWindowAndroid() {}
-
- protected:
-  // ContinueWindow overrides.
-  void ShowUi() override {
-    NOTIMPLEMENTED();
-  }
-
-  void HideUi() override {
-    NOTIMPLEMENTED();
-  }
-
-  DISALLOW_COPY_AND_ASSIGN(ContinueWindowAndroid);
-};
-
-}  // namespace
-
-// static
-std::unique_ptr<HostWindow> HostWindow::CreateContinueWindow() {
-  return base::MakeUnique<ContinueWindowAndroid>();
-}
-
-}  // namespace remoting