Avoid unnecessary invalidation scheduling.

third_party/WebKit/Source/core/css/invalidation/StyleInvalidator.cpp

 // Copyright 2014 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 "core/css/invalidation/StyleInvalidator.h"
 
 #include "core/css/invalidation/InvalidationSet.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/ElementTraversal.h"
@@ skipping 42 matching lines @@
             return;
         }
 
         if (invalidationSet->invalidatesSelf())
             element.setNeedsStyleRecalc(LocalStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::StyleInvalidator));
 
         if (!invalidationSet->isEmpty())
             requiresDescendantInvalidation = true;
     }
 
-    if (invalidationLists.siblings.isEmpty() && !requiresDescendantInvalidation)
+    if (!requiresDescendantInvalidation && (invalidationLists.siblings.isEmpty() || !element.nextSibling()))
         return;
 
     element.setNeedsStyleInvalidation();
+
     PendingInvalidations& pendingInvalidations = ensurePendingInvalidations(element);
-    for (auto& invalidationSet : invalidationLists.siblings) {
-        if (pendingInvalidations.siblings().contains(invalidationSet))
-            continue;
-        pendingInvalidations.siblings().append(invalidationSet);
+    if (element.nextSibling()) {
+        for (auto& invalidationSet : invalidationLists.siblings) {
+            if (pendingInvalidations.siblings().contains(invalidationSet))
+                continue;
+            pendingInvalidations.siblings().append(invalidationSet);
+        }
     }
 
     if (!requiresDescendantInvalidation)
         return;
 
     for (auto& invalidationSet : invalidationLists.descendants) {
         ASSERT(!invalidationSet->wholeSubtreeInvalid());
         if (invalidationSet->isEmpty())
             continue;
         if (pendingInvalidations.descendants().contains(invalidationSet))
@@ skipping 211 matching lines @@
 }
 
 DEFINE_TRACE(StyleInvalidator)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_pendingInvalidationMap);
 #endif
 }
 
 } // namespace blink