[FYI] All-in-one OnCandidateWindow{Show,Update,Hide}

ui/base/ime/text_input_client.h

 // 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_IME_TEXT_INPUT_CLIENT_H_
 #define UI_BASE_IME_TEXT_INPUT_CLIENT_H_
 
 #include "base/basictypes.h"
 #include "base/i18n/rtl.h"
 #include "base/strings/string16.h"
@@ skipping 129 matching lines @@
   // Deletes the current selection plus the specified number of characters
   // before and after the selection or caret. This function should be used
   // instead of calling DeleteRange with GetSelectionRange, because
   // GetSelectionRange may not be the latest value due to asynchronous of IPC
   // between browser and renderer.
   virtual void ExtendSelectionAndDelete(size_t before, size_t after) = 0;
 
   // Ensure the caret is within |rect|.  |rect| is in screen coordinates and
   // may extend beyond the bounds of this TextInputClient.
   virtual void EnsureCaretInRect(const gfx::Rect& rect) = 0;
+
+  // Called when IME shows a candidate window for the ongoing composition.
+  virtual void OnCandidateWindowShow() = 0;
+  // Called when IME updates any appearance of the current candidate window.
+  virtual void OnCandidateWindowUpdate() = 0;
+  // Called when IME hides the candidate window.
+  virtual void OnCandidateWindowHide() = 0;
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_IME_TEXT_INPUT_CLIENT_H_