Migrate CandidateWindow::Entry to string16.

ash/ime/candidate_window_view.h

 // Copyright 2014 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 ASH_IME_CANDIDATE_WINDOW_VIEW_H_
 #define ASH_IME_CANDIDATE_WINDOW_VIEW_H_
 
 #include "ash/ash_export.h"
 #include "ui/base/ime/candidate_window.h"
 #include "ui/views/bubble/bubble_delegate.h"
@@ skipping 43 matching lines @@
   // Shows the lookup table.
   void ShowLookupTable();
 
   // Shows the auxiliary text.
   void ShowAuxiliaryText();
 
   // Shows the preedit text.
   void ShowPreeditText();
 
   // Updates the preedit text.
-  void UpdatePreeditText(const std::string& utf8_text);
+  void UpdatePreeditText(const base::string16& text);
 
   // Updates candidates of the candidate window from |candidate_window|.
   // Candidates are arranged per |orientation|.
   void UpdateCandidates(const ui::CandidateWindow& candidate_window);
 
   void SetCursorBounds(const gfx::Rect& cursor_bounds,
                        const gfx::Rect& composition_head);
 
  private:
   friend class CandidateWindowViewTest;
@@ skipping 50 matching lines @@
   // send OnCandidateWindowOpened and OnCandidateWindowClosed events.
   bool was_candidate_window_open_;
 
   DISALLOW_COPY_AND_ASSIGN(CandidateWindowView);
 };
 
 }  // namespace ime
 }  // namespace ash
 
 #endif  // ASH_IME_CANDIDATE_WINDOW_VIEW_H_