Introduce RemoteInputMethodWin

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
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+++ b/ui/base/ime/remote_input_method_win.h
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+// Copyright (c) 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/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/base/ui_export.h"
+
+namespace ui {
+namespace internal {
+class InputMethodDelegate;
+class RemoteInputMethodDelegateWin;
+}  // namespace internal
+
+class InputMethod;
+
+// 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 RemoteInputMethodPrivateWin 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,
+//   RemoteRootWindowHostWin, which receives IPCs from metro_driver process,
+//   will call RemoteInputMethodPrivateWin::OnCandidatePopupChanged and/or
+//   RemoteInputMethodPrivateWin::OnInputSourceChanged accordingly so that
+//   the state cache should be updated.
+// Caveats: RemoteInputMethodWin does not support InputMethodObserver yet.
+
+// Returns the public interface of RemoteInputMethodWin.
+// Caveats: Currently only one instance of RemoteInputMethodWin is able to run
+// at the same time.
+UI_EXPORT scoped_ptr<InputMethod> CreateRemoteInputMethodWin(
+    internal::InputMethodDelegate* delegate);
+
+// Private interface of RemoteInputMethodWin.
+class UI_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 and
+  // RemoteInputMethodWin::GetInputTextDirection can return the correct
+  // values based on remote IME activities in the metro_driver process.
+  virtual void OnInputSourceChanged(LANGID langid, bool is_ime) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(RemoteInputMethodPrivateWin);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_IME_REMOTE_INPUT_METHOD_WIN_H_