Views: Extract text selection code from Textfield.

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 <stddef.h>
 
 #include <list>
@@ skipping 108 matching lines @@
   // Moves the cursor, see RenderText for additional details.
   // The current composition text will be confirmed.
   void MoveCursor(gfx::BreakType break_type,
                   gfx::VisualCursorDirection direction,
                   gfx::SelectionBehavior selection_behavior);
 
   // Updates the cursor to the specified selection model. Any composition text
   // will be confirmed, which may alter the specified selection range start.
   bool MoveCursorTo(const gfx::SelectionModel& cursor);
 
-  // Helper function to call MoveCursorTo on the TextfieldModel.
+  // Calls the corresponding function on the associated RenderText instance. Any
+  // composition text will be confirmed.
   bool MoveCursorTo(const gfx::Point& point, bool select);
 
   // Selection related methods.
 
   // Returns the selected text.
   base::string16 GetSelectedText() const;
 
   // The current composition text will be confirmed. The selection starts with
   // the range's start position, and ends with the range's end position,
   // therefore the cursor position becomes the end position.
@@ skipping 170 matching lines @@
   //   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_