Views: Extract text selection code from Textfield.

ui/views/controls/textfield/textfield_model.h

Index: ui/views/controls/textfield/textfield_model.h
diff --git a/ui/views/controls/textfield/textfield_model.h b/ui/views/controls/textfield/textfield_model.h
index c66fe6d068083ee7047790207da919042160e663..8b3957b9e0be42ae3354cddbc577b53d69a2efcf 100644
--- a/ui/views/controls/textfield/textfield_model.h
+++ b/ui/views/controls/textfield/textfield_model.h
@@ -126,7 +126,8 @@ class VIEWS_EXPORT TextfieldModel {
   // 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.
+  // Moves the cursor to the text index corresponding to |point|. If |select| is
+  // true, a selection is made with the current selection start index.
   bool MoveCursorTo(const gfx::Point& point, bool select);
 
   // Selection related methods.