Introduce Node::containingTreeScope(), which asserts that the node's root is a tree scope

third_party/WebKit/Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 2191 matching lines @@
     detachAttrNodeAtIndex(attr, index);
     return attr;
 }
 
 void Element::parseAttribute(const QualifiedName& name, const AtomicString&, const AtomicString& value)
 {
     if (name == tabindexAttr) {
         int tabindex = 0;
         if (value.isEmpty()) {
             clearTabIndexExplicitlyIfNeeded();
-            if (treeScope().adjustedFocusedElement() == this) {
+            if (isInTreeScope() && rootTreeScope().adjustedFocusedElement() == this) {

[esprehn, 2016/04/27 07:52:23]

Why do we need to add the check here? We do adjustedFocusedElement() == this in
many places, if that's too expensive then we should add a method to Element that
checks isInTreeScope for you.

[hayato, 2016/05/23 06:22:09]

Done.

Yeah, TreeScope::adjustedFocusedElement() could be expensive.
I introduced Element::adjustedFocusedElementInTreeScope(), and updated callers
of TreeScope::adjustedFocusedElement() to use that. That would be a small
performance gain.

                 // We might want to call blur(), but it's dangerous to dispatch
                 // events here.
                 document().setNeedsFocusedElementCheck();
             }
         } else if (parseHTMLInteger(value, tabindex)) {
             // Clamp tabindex to the range of 'short' to match Firefox's behavior.
             setTabIndexExplicitly(max(static_cast<int>(std::numeric_limits<short>::min()), std::min(tabindex, static_cast<int>(std::numeric_limits<short>::max()))));
         }
     } else if (name == XMLNames::langAttr) {
         pseudoStateChanged(CSSSelector::PseudoLang);
@@ skipping 177 matching lines @@
         frame->selection().setSelection(newSelection,  FrameSelection::CloseTyping | FrameSelection::ClearTypingStyle | FrameSelection::DoNotSetFocus);
         frame->selection().revealSelection();
     } else if (layoutObject() && !layoutObject()->isLayoutPart()) {
         layoutObject()->scrollRectToVisible(boundingBox());
     }
 }
 
 void Element::blur()
 {
     cancelFocusAppearanceUpdate();
-    if (treeScope().adjustedFocusedElement() == this) {
+    if (isInTreeScope() && rootTreeScope().adjustedFocusedElement() == this) {
         Document& doc = document();
         if (doc.page())
             doc.page()->focusController().setFocusedElement(0, doc.frame());
         else
             doc.clearFocusedElement();
     }
 }
 
 bool Element::supportsFocus() const
 {
@@ skipping 701 matching lines @@
 }
 
 inline void Element::updateId(const AtomicString& oldId, const AtomicString& newId)
 {
     if (!isInTreeScope())
         return;
 
     if (oldId == newId)
         return;
 
-    updateId(treeScope(), oldId, newId);
+    updateId(rootTreeScope(), oldId, newId);
 }
 
 inline void Element::updateId(TreeScope& scope, const AtomicString& oldId, const AtomicString& newId)
 {
     DCHECK(isInTreeScope());
     DCHECK_NE(oldId, newId);
 
     if (!oldId.isEmpty())
         scope.removeElementById(oldId, this);
     if (!newId.isEmpty())
@@ skipping 531 matching lines @@
 
 DEFINE_TRACE(Element)
 {
     if (hasRareData())
         visitor->trace(elementRareData());
     visitor->trace(m_elementData);
     ContainerNode::trace(visitor);
 }
 
 } // namespace blink