Revert of Remove remote tree host and some related input and metro_driver code

ui/base/ime/remote_input_method_win.h

Index: ui/base/ime/remote_input_method_win.h
diff --git a/ui/base/ime/remote_input_method_win.h b/ui/base/ime/remote_input_method_win.h
new file mode 100644
index 0000000000000000000000000000000000000000..a1725b32dd30328428f7adff3f311a8e9e2675cd
--- /dev/null
+++ b/ui/base/ime/remote_input_method_win.h
@@ -0,0 +1,100 @@
+// 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_WIN_H_
+#define UI_BASE_IME_REMOTE_INPUT_METHOD_WIN_H_
+
+#include <Windows.h>
+
+#include <string>
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string16.h"
+#include "ui/base/ime/ui_base_ime_export.h"
+#include "ui/gfx/native_widget_types.h"
+
+namespace ui {
+namespace internal {
+class InputMethodDelegate;
+class RemoteInputMethodDelegateWin;
+}  // namespace internal
+
+class InputMethod;
+struct CompositionText;
+
+// RemoteInputMethodWin is a special implementation of ui::InputMethod that
+// works as a proxy of an IME handler running in the metro_driver process.
+// RemoteInputMethodWin works as follows.
+// - Any action to RemoteInputMethodWin should be delegated to the
+//   metro_driver process via RemoteInputMethodDelegateWin.
+// - Data retrieval from RemoteInputMethodPrivateWin is implemented with
+//   data cache. Whenever the IME state in the metro_driver process is changed,
+//   RemoteWindowTreeHostWin, which receives IPCs from metro_driver process,
+//   will call RemoteInputMethodPrivateWin::OnCandidatePopupChanged and/or
+//   RemoteInputMethodPrivateWin::OnInputSourceChanged accordingly so that
+//   the state cache should be updated.
+// - Some IPC messages that represent actions to TextInputClient should be
+//   delegated to RemoteInputMethodPrivateWin so that RemoteInputMethodWin can
+//   work as a real proxy.
+
+// Returns true if |widget| requires RemoteInputMethodWin.
+bool IsRemoteInputMethodWinRequired(gfx::AcceleratedWidget widget);
+
+// Returns the public interface of RemoteInputMethodWin.
+// Caveats: Currently only one instance of RemoteInputMethodWin is able to run
+// at the same time.
+UI_BASE_IME_EXPORT scoped_ptr<InputMethod> CreateRemoteInputMethodWin(
+    internal::InputMethodDelegate* delegate);
+
+// Private interface of RemoteInputMethodWin.
+class UI_BASE_IME_EXPORT RemoteInputMethodPrivateWin {
+ public:
+  RemoteInputMethodPrivateWin();
+
+  // Returns the private interface of RemoteInputMethodWin when and only when
+  // |input_method| is instanciated via CreateRemoteInputMethodWin. Caller does
+  // not take the ownership of the returned object.
+  // As you might notice, this is yet another reinplementation of dynamic_cast
+  // or IUnknown::QueryInterface.
+  static RemoteInputMethodPrivateWin* Get(InputMethod* input_method);
+
+  // Installs RemoteInputMethodDelegateWin delegate. Set NULL to |delegate| to
+  // unregister.
+  virtual void SetRemoteDelegate(
+      internal::RemoteInputMethodDelegateWin* delegate) = 0;
+
+  // Updates internal cache so that subsequent calls of
+  // RemoteInputMethodWin::IsCandidatePopupOpen can return the correct value
+  // based on remote IME activities in the metro_driver process.
+  virtual void OnCandidatePopupChanged(bool visible) = 0;
+
+  // Updates internal cache so that subsequent calls of
+  // RemoteInputMethodWin::GetInputLocale can return the correct values based on
+  // remote IME activities in the metro_driver process.
+  virtual void OnInputSourceChanged(LANGID langid, bool is_ime) = 0;
+
+  // Handles composition-update events occurred in the metro_driver process.
+  // Caveats: This method is designed to be used only with
+  // metro_driver::TextService. In other words, there is no garantee that this
+  // method works a wrapper to call ui::TextInputClient::SetCompositionText.
+  virtual void OnCompositionChanged(
+      const CompositionText& composition_text) = 0;
+
+  // Handles text-commit events occurred in the metro_driver process.
+  // Caveats: This method is designed to be used only with
+  // metro_driver::TextService. In other words, there is no garantee that this
+  // method works a wrapper to call ui::TextInputClient::InsertText. In fact,
+  // this method may call ui::TextInputClient::InsertChar when the text input
+  // type of the focused text input client is TEXT_INPUT_TYPE_NONE.
+  virtual void OnTextCommitted(const base::string16& text) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(RemoteInputMethodPrivateWin);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_IME_REMOTE_INPUT_METHOD_WIN_H_