Simplify handling of BiDi cursor movement

ui/views/controls/textfield/native_textfield_views.cc

Index: ui/views/controls/textfield/native_textfield_views.cc
diff --git a/ui/views/controls/textfield/native_textfield_views.cc b/ui/views/controls/textfield/native_textfield_views.cc
index 8da7db6bf39db3ba702cd835aaffa34d8c5273d5..01ddaa023f90de7bef5bddf88996639bd2d65ba6 100644
--- a/ui/views/controls/textfield/native_textfield_views.cc
+++ b/ui/views/controls/textfield/native_textfield_views.cc
@@ -186,8 +186,7 @@ int NativeTextfieldViews::OnPerformDrop(const DropTargetEvent& event) {
   OnBeforeUserAction();
   skip_input_method_cancel_composition_ = true;
 
-  // TODO(msw): Remove final reference to FindCursorPosition.
-  gfx::SelectionModel drop_destination =
+  gfx::SelectionModel drop_destination_model =
       GetRenderText()->FindCursorPosition(event.location());
   string16 text;
   event.data().GetString(&text);
@@ -199,20 +198,12 @@ int NativeTextfieldViews::OnPerformDrop(const DropTargetEvent& event) {
     gfx::SelectionModel selected;
     model_->GetSelectionModel(&selected);
     // Adjust the drop destination if it is on or after the current selection.
-    size_t max_of_selected_range = std::max(selected.selection_start(),
-                                            selected.selection_end());
-    size_t min_of_selected_range = std::min(selected.selection_start(),
-                                            selected.selection_end());
-    size_t selected_range_length = max_of_selected_range -
-                                   min_of_selected_range;
-    size_t drop_destination_end = drop_destination.selection_end();
-    if (max_of_selected_range <= drop_destination_end)
-      drop_destination_end -= selected_range_length;
-    else if (min_of_selected_range <= drop_destination_end)
-      drop_destination_end = min_of_selected_range;
-    model_->DeleteSelectionAndInsertTextAt(text, drop_destination_end);
+    size_t drop_destination = drop_destination_model.caret_pos();
+    drop_destination -=
+        selected.selection().Intersect(ui::Range(0, drop_destination)).length();
+    model_->DeleteSelectionAndInsertTextAt(text, drop_destination);
   } else {
-    model_->MoveCursorTo(drop_destination);
+    model_->MoveCursorTo(drop_destination_model);
     // Drop always inserts text even if the textfield is not in insert mode.
     model_->InsertText(text);
   }
@@ -248,18 +239,18 @@ void NativeTextfieldViews::SelectRect(const gfx::Point& start,
   if (GetTextInputType() == ui::TEXT_INPUT_TYPE_NONE)
     return;
 
-  gfx::SelectionModel start_pos = GetRenderText()->FindCursorPosition(start);
-  gfx::SelectionModel end_pos = GetRenderText()->FindCursorPosition(end);
+  size_t start_pos = GetRenderText()->FindCursorPosition(start).caret_pos();
+  gfx::SelectionModel end_model = GetRenderText()->FindCursorPosition(end);
+  size_t end_pos = end_model.caret_pos();
 
   OnBeforeUserAction();
   // Merge selection models of "start_pos" and "end_pos" so that
   // selection start is the value from "start_pos", while selection end,
   // caret position, and caret placement are values from "end_pos".
-  if (start_pos.selection_start() == end_pos.selection_end())
-    model_->SelectSelectionModel(end_pos);
+  if (start_pos == end_pos)
+    model_->SelectSelectionModel(end_model);
   else
-    model_->SelectRange(ui::Range(start_pos.selection_start(),
-                                  end_pos.selection_end()));
+    model_->SelectRange(ui::Range(start_pos, end_pos));
 
   OnCaretBoundsChanged();
   SchedulePaint();
@@ -738,8 +729,7 @@ bool NativeTextfieldViews::GetSelectionRange(ui::Range* range) {
 
   gfx::SelectionModel sel;
   model_->GetSelectionModel(&sel);
-  range->set_start(sel.selection_start());
-  range->set_end(sel.selection_end());
+  *range = sel.selection();
   return true;
 }