[selectors4] Implement :focus-within pseudo-class

third_party/WebKit/Source/core/css/SelectorChecker.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc.
  * All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
@@ skipping 896 matching lines @@
         return true;
       if (mode_ == kResolvingStyle) {
         if (context.in_rightmost_compound) {
           element_style_->SetAffectedByFocus();
         } else {
           element_style_->SetUnique();
           element.SetChildrenOrSiblingsAffectedByFocus();
         }
       }
       return MatchesFocusPseudoClass(element);
+    case CSSSelector::kPseudoFocusWithin:
+      if (mode_ == kSharingRules)
+        return true;
+      if (mode_ == kResolvingStyle) {
+        if (context.in_rightmost_compound) {
+          element_style_->SetAffectedByFocusWithin();
+        } else {
+          element_style_->SetUnique();
+          element.SetChildrenOrSiblingsAffectedByFocusWithin();
+        }
+      }
+      probe::forcePseudoState(&element, CSSSelector::kPseudoFocusWithin,
+                              &force_pseudo_state);
+      if (force_pseudo_state)
+        return true;
+      return element.HasFocusWithin();
     case CSSSelector::kPseudoHover:
       if (mode_ == kSharingRules)
         return true;
       if (mode_ == kResolvingStyle) {
         if (context.in_rightmost_compound) {
           element_style_->SetAffectedByHover();
         } else {
           element_style_->SetUnique();
           element.SetChildrenOrSiblingsAffectedByHover();
         }
@@ skipping 408 matching lines @@
 bool SelectorChecker::MatchesFocusPseudoClass(const Element& element) {
   bool force_pseudo_state = false;
   probe::forcePseudoState(const_cast<Element*>(&element),
                           CSSSelector::kPseudoFocus, &force_pseudo_state);
   if (force_pseudo_state)
     return true;
   return element.IsFocused() && IsFrameFocused(element);
 }
 
 }  // namespace blink