Implement :valid and :invalid pseudoclass for <form>

Source/core/css/resolver/SharedStyleFinder.cpp

Index: Source/core/css/resolver/SharedStyleFinder.cpp
diff --git a/Source/core/css/resolver/SharedStyleFinder.cpp b/Source/core/css/resolver/SharedStyleFinder.cpp
index ce16c0df1f0d4b7ef17a08556a3e785caf1906c7..c1130eab7f6c39556b50302751b124eccbd4d27f 100644
--- a/Source/core/css/resolver/SharedStyleFinder.cpp
+++ b/Source/core/css/resolver/SharedStyleFinder.cpp
@@ -84,7 +84,7 @@ bool SharedStyleFinder::canShareStyleWithControl(Element& candidate) const
         if (willValidate != element().willValidate())
             return false;
 
-        if (willValidate && (candidate.isValidFormControlElement() != element().isValidFormControlElement()))
+        if (willValidate && (candidate.isValidElement() != element().isValidElement()))
             return false;
 
         if (candidate.isInRange() != element().isInRange())
@@ -242,6 +242,9 @@ bool SharedStyleFinder::canShareStyleWithElement(Element& candidate) const
         || toHTMLOptionElement(candidate).spatialNavigationFocused() != toHTMLOptionElement(element()).spatialNavigationFocused()))
         return false;
 
+    if (candidate.isValidElement() != element().isValidElement())
+        return false;
+
     // FIXME: This line is surprisingly hot, we may wish to inline hasDirectionAuto into StyleResolver.
     if (candidate.isHTMLElement() && toHTMLElement(candidate).hasDirectionAuto())
         return false;