Don't match empty style rules.

Source/core/css/ElementRuleCollector.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/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 262 matching lines @@
         return false;
     return true;
 }
 
 void ElementRuleCollector::collectRuleIfMatches(const RuleData& ruleData, CascadeScope cascadeScope, CascadeOrder cascadeOrder, const MatchRequest& matchRequest, RuleRange& ruleRange)
 {
     if (m_canUseFastReject && m_selectorFilter.fastRejectSelector<RuleData::maximumIdentifierCount>(ruleData.descendantSelectorIdentifierHashes()))
         return;
 
     StyleRule* rule = ruleData.rule();
+
+    // If the rule has no properties to apply, then ignore it in the non-debug mode.
+    const StylePropertySet& properties = rule->properties();
+    if (properties.isEmpty() && !matchRequest.includeEmptyRules)
+        return;
+
     SelectorChecker::MatchResult result;
     if (ruleMatches(ruleData, matchRequest.scope, &result)) {
-        // If the rule has no properties to apply, then ignore it in the non-debug mode.
-        const StylePropertySet& properties = rule->properties();
-        if (properties.isEmpty() && !matchRequest.includeEmptyRules)
-            return;
         // FIXME: Exposing the non-standard getMatchedCSSRules API to web is the only reason this is needed.
         if (m_sameOriginOnly && !ruleData.hasDocumentSecurityOrigin())
             return;
 
         PseudoId dynamicPseudo = result.dynamicPseudo;
         // If we're matching normal rules, set a pseudo bit if
         // we really just matched a pseudo-element.
         if (dynamicPseudo != NOPSEUDO && m_pseudoStyleRequest.pseudoId == NOPSEUDO) {
             if (m_mode == SelectorChecker::CollectingCSSRules || m_mode == SelectorChecker::CollectingStyleRules)
                 return;
@@ skipping 44 matching lines @@
     // information about "scope".
     int firstRuleIndex = -1, lastRuleIndex = -1;
     RuleRange ruleRange(firstRuleIndex, lastRuleIndex);
     // FIXME: Verify whether it's ok to ignore CascadeScope here.
     collectMatchingRules(MatchRequest(ruleSet), ruleRange);
 
     return !m_matchedRules.isEmpty();
 }
 
 } // namespace blink