Add lots more tests for SelectorQuery fast paths.

third_party/WebKit/Source/core/dom/SelectorQuery.cpp

Index: third_party/WebKit/Source/core/dom/SelectorQuery.cpp
diff --git a/third_party/WebKit/Source/core/dom/SelectorQuery.cpp b/third_party/WebKit/Source/core/dom/SelectorQuery.cpp
index b6f54ce4336e924113f141e24f70e1d805b1f8b6..3d4937ee77f87ec4852803899537f12ee9e85d8c 100644
--- a/third_party/WebKit/Source/core/dom/SelectorQuery.cpp
+++ b/third_party/WebKit/Source/core/dom/SelectorQuery.cpp
@@ -269,6 +269,7 @@ void SelectorQuery::FindTraverseRootsAndExecute(
       const AtomicString& class_name = selector->Value();
       Element* element = ElementTraversal::FirstWithin(root_node);
       while (element) {
+        QUERY_STATS_INCREMENT(fast_class);
         if (HasClassName(*element, class_name)) {
           ExecuteForTraverseRoot<SelectorQueryTrait>(*element, root_node,
                                                      output);