Bug 783213 - Part 1: Only apply the :active and :hover quirk to links, and not when the selector uses other pseudo-classes. r=dbaron

layout/style/nsCSSRuleProcessor.cpp

@@ -1458,18 +1458,25 @@ static bool ValueIncludes(const nsSubstring& aValueList,
   return false;
 }
 
-// Return whether we should apply a "global" (i.e., universal-tag)
-// selector for event states in quirks mode.  Note that
-// |IsLink()| is checked separately by the caller, so we return
-// false for |nsGkAtoms::a|, which here means a named anchor.
-inline bool IsQuirkEventSensitive(nsIAtom *aContentTag)
+// Return whether the selector matches conditions for the :active and
+// :hover quirk.
+static inline bool ActiveHoverQuirkMatches(nsCSSSelector* aSelector)
 {
-  return bool ((nsGkAtoms::button == aContentTag) ||
-                 (nsGkAtoms::img == aContentTag)    ||
-                 (nsGkAtoms::input == aContentTag)  ||
-                 (nsGkAtoms::label == aContentTag)  ||
-                 (nsGkAtoms::select == aContentTag) ||
-                 (nsGkAtoms::textarea == aContentTag));
+  if (aSelector->HasTagSelector() || aSelector->mAttrList ||
+      aSelector->mIDList || aSelector->mClassList) {
+    return false;
+  }
+
+  // No pseudo-class other than :active and :hover.
+  for (nsPseudoClassList* pseudoClass = aSelector->mPseudoClassList;
+       pseudoClass; pseudoClass = pseudoClass->mNext) {
+    if (pseudoClass->mType != nsCSSPseudoClasses::ePseudoClass_hover &&
+        pseudoClass->mType != nsCSSPseudoClasses::ePseudoClass_active) {
+      return false;
+    }
+  }
+
+  return true;
 }
 
 
@@ -1676,21 +1683,18 @@ StateSelectorMatches(Element* aElement,
   const bool isNegated = aDependence != nullptr;
 
   // Bit-based pseudo-classes
-  if (aStatesToCheck.HasAtLeastOneOfStates(NS_EVENT_STATE_HOVER | NS_EVENT_STATE_ACTIVE) &&
+  if (aStatesToCheck.HasAtLeastOneOfStates(NS_EVENT_STATE_ACTIVE |
+                                           NS_EVENT_STATE_HOVER) &&
       aTreeMatchContext.mCompatMode == eCompatibility_NavQuirks &&
-      // global selector:
-      !aSelector->HasTagSelector() && !aSelector->mIDList &&
-      !aSelector->mClassList && !aSelector->mAttrList &&
+      ActiveHoverQuirkMatches(aSelector) &&
       // This (or the other way around) both make :not() asymmetric
       // in quirks mode (and it's hard to work around since we're
       // testing the current mNegations, not the first
       // (unnegated)). This at least makes it closer to the spec.
       !isNegated &&
-      // important for |IsQuirkEventSensitive|:
-      aElement->IsHTML() && !nsCSSRuleProcessor::IsLink(aElement) &&
-      !IsQuirkEventSensitive(aElement->Tag())) {
-    // In quirks mode, only make certain elements sensitive to
-    // selectors ":hover" and ":active".
+      aElement->IsHTML() && !nsCSSRuleProcessor::IsLink(aElement)) {
+    // In quirks mode, only make links sensitive to selectors ":active"
+    // and ":hover".
     return false;
   }