Supports the invisible underline for native input fields.

ui/views/controls/textfield/textfield_model.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 UI_VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_MODEL_H_
 #define UI_VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_MODEL_H_
 
 #include <list>
 #include <vector>
 
@@ skipping 249 matching lines @@
                   size_t new_cursor_pos);
 
   void ClearComposition();
 
   // The TextfieldModel::Delegate instance should be provided by the owner.
   Delegate* delegate_;
 
   // The stylized text, cursor, selection, and the visual layout model.
   scoped_ptr<gfx::RenderText> render_text_;
 
+  // The composition range.
+  gfx::Range composition_range_;
+
   typedef std::list<internal::Edit*> EditHistory;
   EditHistory edit_history_;
 
   // An iterator that points to the current edit that can be undone.
   // This iterator moves from the |end()|, meaining no edit to undo,
   // to the last element (one before |end()|), meaning no edit to redo.
   //
   // There is no edit to undo (== end()) when:
   //   1) in initial state. (nothing to undo)
   //   2) very 1st edit is undone.
   //   3) all edit history is removed.
   // There is no edit to redo (== last element or no element) when:
   //   1) in initial state. (nothing to redo)
   //   2) new edit is added. (redo history is cleared)
   //   3) redone all undone edits.
   EditHistory::iterator current_edit_;
 
   DISALLOW_COPY_AND_ASSIGN(TextfieldModel);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_MODEL_H_