HTMLTextAreaElement.setSelectionRange should not change focus.

Source/core/html/HTMLTextAreaElement.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, 2008, 2010 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 353 matching lines @@
         return;
 
     m_value = normalizedValue;
     setInnerEditorValue(m_value);
     if (eventBehavior == DispatchNoEvent)
         setLastChangeWasNotUserEdit();
     updatePlaceholderVisibility(false);
     setNeedsStyleRecalc(SubtreeStyleChange);
     m_suggestedValue = String();
 
-    // Set the caret to the end of the text value.
-    if (document().focusedElement() == this) {
+    if (renderer() && valid()) {

[tkent, 2014/07/23 02:25:24]

I don't understand this code at all.  Why valid() is involved?

[yoichio, 2014/07/23 10:39:07]

Move validity check to setSelectionRange.

HTMLTextFormControlElement::setSelectionRange calls layout.
It suppose textform's validity is updated.
textarea-live-pseudo-selectors tests it in L71.
http://src.chromium.org/viewvc/blink/trunk/LayoutTests/fast/forms/resources/t...

[tkent, 2014/07/24 01:04:22]

ok, I understand that setNeedsValidityCheck() in setValue is too late.  Probably
we should move it to setValueCommon.  Putting it to setSelectionRange looks
weird.

+        // Set the caret to the end of the text value.
         unsigned endOfString = m_value.length();
-        setSelectionRange(endOfString, endOfString);
+        setSelectionRange(endOfString, endOfString, SelectionHasNoDirection, NotChangeSelection);
     }
 
     notifyFormStateChanged();
     if (eventBehavior == DispatchNoEvent) {
         setTextAsOfLastFormControlChangeEvent(normalizedValue);
     } else {
         if (eventBehavior == DispatchInputAndChangeEvent)
             dispatchFormControlInputEvent();
         dispatchFormControlChangeEvent();
     }
@@ skipping 168 matching lines @@
 {
     return true;
 }
 
 bool HTMLTextAreaElement::supportsAutofocus() const
 {
     return true;
 }
 
 }