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
new file mode 100644
index 0000000000000000000000000000000000000000..54834064a7130b2841b85175204fdcdc854ea45d
--- /dev/null
+++ b/ui/base/ime/remote_input_method_win.h
@@ -0,0 +1,75 @@
+// 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,
+//   someone needs to call RemoteInputMethodPrivateWin::OnCandidatePopupChanged

[Seigo Nonaka, 2013/11/18 20:00:27]

Could you add example for this "someone"?

[yukawa, 2013/11/19 07:17:51]

Done.

+//   and RemoteInputMethodPrivateWin::OnLanguageChanged to update the data
+//   cache.
+// 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(

[Seigo Nonaka, 2013/11/18 20:00:27]

How about moving this function into static class function as "Create"?

[yukawa, 2013/11/19 07:17:51]

Sorry, to which class?

1)
class UI_EXPORT RemoteInputMethodWin {
 public:
  static scoped_ptr<InputMethod> Create(internal::InputMethodDelegate*
delegate);

 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(RemoteInputMethodWin);
};

2)
class UI_EXPORT RemoteInputMethodPrivateWin {
 public:
  static scoped_ptr<InputMethod> Create(internal::InputMethodDelegate*
delegate);
  ...
};

1) is contradict to your another comment that we should not use static-method
only class.

2) does not make sense because RemoteInputMethodPrivateWin::Create does not
create an instance of RemoteInputMethodPrivateWin despite its method name.

[Seigo Nonaka, 2013/11/20 04:14:29]

Sorry I miss understood. Current comment is fine.
On 2013/11/19 07:17:51, yukawa wrote:

+    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 additional delegate that is required by RemoteInputMethodWin.

[Seigo Nonaka, 2013/11/18 20:00:27]

Sorry, I'm bit confused with this comment.
An instance of this class only accept one delegate, right?
"Installs additional delegate" sounds like there are many delegates.
If this class can accept multiple delegates, please rename this class as
"AddRemoteDelegate".

[yukawa, 2013/11/19 07:17:51]

No, multiple delegates are not supported.  Updated the comment.

+  virtual void SetRemoteDelegate(
+      internal::RemoteInputMethodDelegateWin* delegate) = 0;
+
+  // Synchronizes that the visibility of IME's popup window in the remote
+  // process. RemoteInputMethodWin::IsCandidatePopupOpen relies on this
+  // notification.
+  virtual void OnCandidatePopupChanged(bool visible) = 0;
+
+  // Synchronizes that Win32 LANGID and the presence of IME in the remote
+  // process. RemoteInputMethodWin::GetInputLocale and
+  // RemoteInputMethodWin::GetInputLocale rely on this notification.
+  virtual void OnLanguageChanged(LANGID langid, bool is_ime) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(RemoteInputMethodPrivateWin);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_IME_REMOTE_INPUT_METHOD_WIN_H_