Introduce TsfEventRouter.

ui/base/win/tsf_event_router.h

Index: ui/base/win/tsf_event_router.h
diff --git a/ui/base/win/tsf_event_router.h b/ui/base/win/tsf_event_router.h
new file mode 100644
index 0000000000000000000000000000000000000000..e4eb2584e700214dedea4826ae445196f299e7ec
--- /dev/null
+++ b/ui/base/win/tsf_event_router.h
@@ -0,0 +1,60 @@
+// Copyright (c) 2012 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_WIN_TSF_EVENT_ROUTER_H_
+#define UI_BASE_WIN_TSF_EVENT_ROUTER_H_
+
+#include <msctf.h>
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "ui/base/ime/text_input_type.h"
+#include "ui/base/ui_export.h"
+
+struct ITfDocumentMgr;
+
+namespace ui {
+
+// This is an abstract interface that monitors events associated with TSF and
+// forwards them to the observer. In order to manage the life cycle of this
+// object by scoped_refptr and the implementation class of this interface is COM
+// class anyway, this interface is derived from IUnknown.
+class TsfEventRouter : public IUnknown {
+ public:
+  typedef base::Callback<void ()> TextUpdatedCallback;
+  typedef base::Callback<void (size_t window_count)>
+      CandidateWindowCountChangedCallback;
+
+  virtual ~TsfEventRouter();
+
+  // Sets |manager| to be monitored. |manager| can be NULL.
+  virtual void SetManager(ITfThreadMgr* manager) = 0;
+
+  // Returns true if the IME is composing texts.
+  virtual bool IsImeComposing() = 0;
+
+  // Sets the callback function which is invoked when the text contents is
+  // updated.
+  virtual void SetTextUpdatedCallback(
+      const TextUpdatedCallback& callback) = 0;
+
+  // Sets the callback function which is invoked when the number of currently
+  // candidate window opened is changed.
+  virtual void SetCandidateWindowStatusChangedCallback(
+      const CandidateWindowCountChangedCallback& callback) = 0;
+
+  // Factory function, creates a new instance and retunrns ownership.
+  static UI_EXPORT TsfEventRouter* Create();
+
+ protected:
+  // Create should be used instead.
+  TsfEventRouter();
+
+  DISALLOW_COPY_AND_ASSIGN(TsfEventRouter);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_WIN_TSF_EVENT_ROUTER_H_