Don't schedule invalidations when attributes changed if not needed or incorrect.

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 "config.h"
 
 #include "core/css/invalidation/StyleInvalidator.h"
 
 #include "core/css/invalidation/DescendantInvalidationSet.h"
@@ skipping 10 matching lines @@
 {
     if (Element* documentElement = document.documentElement())
         invalidate(*documentElement);
     document.clearChildNeedsStyleInvalidation();
     document.clearNeedsStyleInvalidation();
     clearPendingInvalidations();
 }
 
 void StyleInvalidator::scheduleInvalidation(PassRefPtr<DescendantInvalidationSet> invalidationSet, Element& element)
 {
+    ASSERT(element.inActiveDocument() && element.styleChangeType() < SubtreeStyleChange);

[esprehn, 2014/05/08 05:19:06]

Lets split this into two ASSERTs, one per line. When you combine asserts of
totally different properties like this it's hard to know which one is hit in a
stack trace.

[chrishtr, 2014/05/08 05:29:18]

Done.

     InvalidationList& list = ensurePendingInvalidationList(element);
     // If we're already going to invalidate the whole subtree we don't need to store any new sets.
     if (!list.isEmpty() && list.last()->wholeSubtreeInvalid())
         return;
     // If this set would invalidate the whole subtree we can discard all existing sets.
     if (invalidationSet->wholeSubtreeInvalid())
         list.clear();
     list.append(invalidationSet);
     element.setNeedsStyleInvalidation();
 }
 
 StyleInvalidator::InvalidationList& StyleInvalidator::ensurePendingInvalidationList(Element& element)
 {
     PendingInvalidationMap::AddResult addResult = m_pendingInvalidationMap.add(&element, nullptr);
     if (addResult.isNewEntry)
         addResult.storedValue->value = adoptPtr(new InvalidationList);
     return *addResult.storedValue->value;
 }
 
 void StyleInvalidator::clearInvalidation(Node& node)
 {
     if (node.isElementNode() && node.needsStyleInvalidation())
         m_pendingInvalidationMap.remove(toElement(&node));
-    node.clearChildNeedsStyleInvalidation();
-    node.clearNeedsStyleInvalidation();
 }
 
 void StyleInvalidator::clearPendingInvalidations()
 {
     m_pendingInvalidationMap.clear();
 }
 
 StyleInvalidator::StyleInvalidator()
 {
 }
@@ skipping 83 matching lines @@
             element.setNeedsStyleRecalc(LocalStyleChange);
     }
 
     element.clearChildNeedsStyleInvalidation();
     element.clearNeedsStyleInvalidation();
 
     return thisElementNeedsStyleRecalc;
 }
 
 } // namespace WebCore