Remove remote tree host and some related input and metro_driver code

ui/base/ime/remote_input_method_delegate_win.h

-// Copyright 2013 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 UI_BASE_IME_REMOTE_INPUT_METHOD_DELEGATE_WIN_H_
-#define UI_BASE_IME_REMOTE_INPUT_METHOD_DELEGATE_WIN_H_
-
-#include <stdint.h>
-
-#include <vector>
-
-#include "ui/base/ime/ui_base_ime_export.h"
-#include "ui/gfx/geometry/rect.h"
-
-namespace ui {
-namespace internal {
-
-// An interface implemented by the object to forward events that should be
-// handled by the IME which is running in the remote metro_driver process.
-class UI_BASE_IME_EXPORT RemoteInputMethodDelegateWin {
- public:
-  virtual ~RemoteInputMethodDelegateWin() {}
-
-  // Notifies that composition should be canceled (if any).
-  virtual void CancelComposition() = 0;
-
-  // Notifies that properties of the focused TextInputClient is changed.
-  // Note that an empty |input_scopes| represents that TextInputType is
-  // TEXT_INPUT_TYPE_NONE.
-  // Caveats: |input_scopes| is defined as std::vector<int32_t> rather than
-  // std::vector<InputScope> because the wire format of IPC message
-  // MetroViewerHostMsg_ImeTextInputClientUpdated uses std::vector<int32_t> to
-  // avoid dependency on <InputScope.h> header.
-  virtual void OnTextInputClientUpdated(
-      const std::vector<int32_t>& input_scopes,
-      const std::vector<gfx::Rect>& composition_character_bounds) = 0;
-};
-
-}  // namespace internal
-}  // namespace ui
-
-#endif  // UI_BASE_IME_REMOTE_INPUT_METHOD_DELEGATE_WIN_H_