Add text offset to OnSurroundingTextChanged

ui/views/controls/textfield/textfield.cc

 // Copyright (c) 2012 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/views/controls/textfield/textfield.h"
 
 #include <string>
 
 #include "base/trace_event/trace_event.h"
 #include "ui/accessibility/ax_view_state.h"
@@ skipping 1540 matching lines @@
 
 bool Textfield::SetSelectionRange(const gfx::Range& range) {
   if (!ImeEditingAllowed() || !range.IsValid())
     return false;
   OnBeforeUserAction();
   SelectRange(range);
   OnAfterUserAction();
   return true;
 }
 
+uint32 Textfield::GetSelectionOffset() const {
+  return 0;

[Shu Chen, 2015/08/12 07:23:16]

Why always return 0?

[rsadam, 2015/08/12 21:46:52]

From my understanding textfield.h is for all native textboxes e.g omnibox. These
return the complete surrounding text, and so the offset is always 0. We could
change textfield.h behaviour to mimic blink, and only return the last 100
characters.

[Shu Chen, 2015/08/13 01:27:24]

Let's not change the existing behavior for now.
Returning zero here sounds fine.

+}
+
 bool Textfield::DeleteRange(const gfx::Range& range) {
   if (!ImeEditingAllowed() || range.is_empty())
     return false;
 
   OnBeforeUserAction();
   model_->SelectRange(range);
   if (model_->HasSelection()) {
     model_->DeleteSelection();
     UpdateAfterChange(true, true);
   }
@@ skipping 321 matching lines @@
     RequestFocus();
   model_->MoveCursorTo(mouse);
   if (!selection_clipboard_text.empty()) {
     model_->InsertText(selection_clipboard_text);
     UpdateAfterChange(true, true);
   }
   OnAfterUserAction();
 }
 
 }  // namespace views