Clean up of SelectionModel

ui/gfx/selection_model.cc

 // Copyright (c) 2011 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.
 
 #include "ui/gfx/selection_model.h"
 
 namespace gfx {
 
 SelectionModel::SelectionModel() {
   Init(0, 0, 0, LEADING);
 }
 
 SelectionModel::SelectionModel(size_t pos) {
   Init(pos, pos, pos, LEADING);
 }
 
 SelectionModel::SelectionModel(size_t start, size_t end) {
-  Init(start, end, end, LEADING);
+  if (start < end)

[msw, 2011/09/29 02:20:21]

Perhaps this condition deserves an explanation:
"The caret position should trail the selection end's previous grapheme in this
case [because/in order to/so that] ..."

[xji, 2011/10/03 23:18:57]

this ctor is removed.

+    Init(start, end, end, TRAILING_OF_PREVIOUS_GRAPHEME);
+  else
+    Init(start, end, end, LEADING);
 }
 
 SelectionModel::SelectionModel(size_t end,
                                size_t pos,
                                CaretPlacement placement) {
   Init(end, end, pos, placement);
 }
 
 SelectionModel::SelectionModel(size_t start,
                                size_t end,
@@ skipping 16 matching lines @@
                           size_t end,
                           size_t pos,
                           CaretPlacement placement) {
   selection_start_ = start;
   selection_end_ = end;
   caret_pos_ = pos;
   caret_placement_ = placement;
 }
 
 }  // namespace gfx