CSS: Reduce style invalidation with sibling combinators

third_party/WebKit/Source/core/css/RuleFeatureSetTest.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/css/RuleFeature.h"
 
 #include "core/css/CSSSelectorList.h"
 #include "core/css/RuleSet.h"
 #include "core/css/StylePropertySet.h"
@@ skipping 83 matching lines @@
     {
         EXPECT_EQ(0u, invalidationSets.size());
     }
 
     void expectSelfInvalidation(InvalidationSetVector& invalidationSets)
     {
         EXPECT_EQ(1u, invalidationSets.size());
         EXPECT_TRUE(invalidationSets[0]->invalidatesSelf());
     }
 
+    void expectNoSelfInvalidation(InvalidationSetVector& invalidationSets)
+    {
+        EXPECT_EQ(1u, invalidationSets.size());
+        EXPECT_FALSE(invalidationSets[0]->invalidatesSelf());
+    }
+
     void expectClassInvalidation(const AtomicString& className, InvalidationSetVector& invalidationSets)
     {
         EXPECT_EQ(1u, invalidationSets.size());
         HashSet<AtomicString> classes = classSet(*invalidationSets[0]);
         EXPECT_EQ(1u, classes.size());
         EXPECT_TRUE(classes.contains(className));
     }
 
     void expectSiblingInvalidation(unsigned maxDirectAdjacentSelectors, const AtomicString& siblingName, InvalidationSetVector& invalidationSets)
     {
@@ skipping 80 matching lines @@
     updateInvalidationSets(".o + .p");
 
     InvalidationLists invalidationLists;
     collectInvalidationSetsForClass(invalidationLists, "o");
     expectNoInvalidation(invalidationLists.descendants);
     expectSiblingInvalidation(1, "p", invalidationLists.siblings);
 }
 
 TEST_F(RuleFeatureSetTest, interleavedDescendantSibling3)
 {
-    updateInvalidationSets(".n .o + .p");
+    updateInvalidationSets(".m + .n .o + .p");
 
     InvalidationLists invalidationLists;
     collectInvalidationSetsForClass(invalidationLists, "n");
+    expectNoSelfInvalidation(invalidationLists.descendants);
     expectClassInvalidation("p", invalidationLists.descendants);
     expectNoInvalidation(invalidationLists.siblings);
 }
 
 TEST_F(RuleFeatureSetTest, interleavedDescendantSibling4)
 {
     updateInvalidationSets(".m + .n .o + .p");
 
     InvalidationLists invalidationLists;
     collectInvalidationSetsForClass(invalidationLists, "m");
@@ skipping 92 matching lines @@
 TEST_F(RuleFeatureSetTest, tagName)
 {
     updateInvalidationSets(":valid e");
 
     InvalidationLists invalidationLists;
     collectInvalidationSetsForPseudoClass(invalidationLists, CSSSelector::PseudoValid);
     expectTagNameInvalidation("e", invalidationLists.descendants);
 }
 
 } // namespace blink