Implement a simple version of SelectorQuery.

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

Index: third_party/WebKit/Source/core/css/SelectorChecker.h
diff --git a/third_party/WebKit/Source/core/css/SelectorChecker.h b/third_party/WebKit/Source/core/css/SelectorChecker.h
index a8271836d63115bb6e6acd1840d5e70389efc8a3..8ca59a79fac0025b39aed43b5abdf2cf13ba9d58 100644
--- a/third_party/WebKit/Source/core/css/SelectorChecker.h
+++ b/third_party/WebKit/Source/core/css/SelectorChecker.h
@@ -99,8 +99,17 @@ public:
         unsigned specificity;
     };
 
-    bool match(const SelectorCheckingContext&, MatchResult&) const;
-    bool match(const SelectorCheckingContext&) const;
+    bool match(const SelectorCheckingContext& context, MatchResult& result) const
+    {
+        ASSERT(context.selector);
+        return matchSelector(context, result) == SelectorMatches;
+    }
+
+    bool match(const SelectorCheckingContext& context) const
+    {
+        MatchResult ignoreResult;
+        return match(context, ignoreResult);
+    }
 
     static bool matchesFocusPseudoClass(const Element&);