Revert of Implement :valid and :invalid pseudoclass for <form>

Source/core/html/HTMLFormElement.cpp

Index: Source/core/html/HTMLFormElement.cpp
diff --git a/Source/core/html/HTMLFormElement.cpp b/Source/core/html/HTMLFormElement.cpp
index 8412cc5e3ae9d23c1bc9306677fdd918672c8d78..013dfd394be8dbef75ae85657bcc183e80b7aa84 100644
--- a/Source/core/html/HTMLFormElement.cpp
+++ b/Source/core/html/HTMLFormElement.cpp
@@ -109,16 +109,6 @@
     HTMLElement::trace(visitor);
 }
 
-bool HTMLFormElement::willValidate() const
-{
-    return true;
-}
-
-bool HTMLFormElement::isValidElement()
-{
-    return checkValidity();
-}
-
 bool HTMLFormElement::rendererIsNeeded(const RenderStyle& style)
 {
     if (!m_wasDemoted)
@@ -726,14 +716,6 @@
     return 0;
 }
 
-void HTMLFormElement::setNeedsValidityCheck()
-{
-    // For now unconditionally order style recalculation, which triggers
-    // validity recalculation. In the near future, implement validity cache and
-    // recalculate style only if it changed.
-    setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::createWithExtraData(StyleChangeReason::PseudoClass, StyleChangeExtraData::Invalid));
-}
-
 bool HTMLFormElement::checkValidity()
 {
     return !checkInvalidControlsAndCollectUnhandled(0);