Use FrameSelection::selectedText where possible.

third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 336 matching lines @@
 
     ASSERT(index >= 0);
     return index;
 }
 
 void HTMLTextFormControlElement::setSelectionRange(int start, int end, TextFieldSelectionDirection direction, NeedToDispatchSelectEvent eventBehaviour, SelectionOption selectionOption)
 {
     if (openShadowRoot() || !isTextFormControl() || !inDocument())
         return;
 
+    document().updateLayoutIgnorePendingStylesheets();

[tkent, 2015/10/20 23:11:32]

nit: Add a comment why we need to update layout.

+
     const int editorValueLength = static_cast<int>(innerEditorValue().length());
     ASSERT(editorValueLength >= 0);
     end = std::max(std::min(end, editorValueLength), 0);
     start = std::min(std::max(start, 0), end);
     cacheSelection(start, end, direction);
 
     if (selectionOption == NotChangeSelection || (selectionOption == ChangeSelectionIfFocused && document().focusedElement() != this)) {
         if (eventBehaviour == DispatchSelectEvent)
             scheduleSelectEvent();
         return;
@@ skipping 648 matching lines @@
 }
 
 void HTMLTextFormControlElement::copyNonAttributePropertiesFromElement(const Element& source)
 {
     const HTMLTextFormControlElement& sourceElement = static_cast<const HTMLTextFormControlElement&>(source);
     m_lastChangeWasUserEdit = sourceElement.m_lastChangeWasUserEdit;
     HTMLFormControlElement::copyNonAttributePropertiesFromElement(source);
 }
 
 } // namespace blink