Avoid unnecessary invalidation scheduling.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 609 matching lines @@
         m_fontSelector->registerForInvalidationCallbacks(this);
 }
 
 void StyleEngine::platformColorsChanged()
 {
     if (m_resolver)
         m_resolver->invalidateMatchedPropertiesCache();
     document().setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::PlatformColorChange));
 }
 
+bool StyleEngine::shouldSkipInvalidationFor(const Element& element) const
+{
+    if (!isMaster())
+        return true;

[rune, 2015/12/10 08:08:52]

Should I rely on non-master documents having a null-resolver and
ASSERT(isMaster()) below the resolver() check instead of this if-check?

[esprehn, 2015/12/10 08:53:47]

the non master will also not be active, so it'll fail the inActiveDocument()

+    if (!resolver())
+        return true;
+    if (!element.inActiveDocument())
+        return true;
+    if (!element.parentNode())
+        return true;
+    return element.parentNode()->styleChangeType() >= SubtreeStyleChange;
+}
+
 void StyleEngine::classChangedForElement(const SpaceSplitString& changedClasses, Element& element)
 {
-    ASSERT(isMaster());
+    if (shouldSkipInvalidationFor(element))

[esprehn, 2015/12/10 08:53:47]

classChangedForElement is guarded by:

    bool testShouldInvalidateStyle = inActiveDocument() && styleResolver;


idAttribute and others are guarded the same since accessing the styleEngine()
will crash if you're not in an active document.

I don't think you need either of those checks in the skip method, it should
perhaps just assert?

[esprehn, 2015/12/10 08:57:01]

Oh I see you removed all those checks, this seems fine then.

+        return;
     InvalidationLists invalidationLists;
     unsigned changedSize = changedClasses.size();
     RuleFeatureSet& ruleFeatureSet = ensureResolver().ensureUpdatedRuleFeatureSet();
     for (unsigned i = 0; i < changedSize; ++i)
         ruleFeatureSet.collectInvalidationSetsForClass(invalidationLists, element, changedClasses[i]);
     m_styleInvalidator.scheduleInvalidationSetsForElement(invalidationLists, element);
 }
 
 void StyleEngine::classChangedForElement(const SpaceSplitString& oldClasses, const SpaceSplitString& newClasses, Element& element)
 {
-    ASSERT(isMaster());
+    if (shouldSkipInvalidationFor(element))
+        return;
+
     if (!oldClasses.size()) {
         classChangedForElement(newClasses, element);
         return;
     }
 
     // Class vectors tend to be very short. This is faster than using a hash table.
     BitVector remainingClassBits;
     remainingClassBits.ensureSize(oldClasses.size());
 
     InvalidationLists invalidationLists;
@@ skipping 20 matching lines @@
             continue;
         // Class was removed.
         ruleFeatureSet.collectInvalidationSetsForClass(invalidationLists, element, oldClasses[i]);
     }
 
     m_styleInvalidator.scheduleInvalidationSetsForElement(invalidationLists, element);
 }
 
 void StyleEngine::attributeChangedForElement(const QualifiedName& attributeName, Element& element)
 {
-    ASSERT(isMaster());
+    if (shouldSkipInvalidationFor(element))
+        return;
+
     InvalidationLists invalidationLists;
     ensureResolver().ensureUpdatedRuleFeatureSet().collectInvalidationSetsForAttribute(invalidationLists, element, attributeName);
     m_styleInvalidator.scheduleInvalidationSetsForElement(invalidationLists, element);
 }
 
 void StyleEngine::idChangedForElement(const AtomicString& oldId, const AtomicString& newId, Element& element)
 {
-    ASSERT(isMaster());
+    if (shouldSkipInvalidationFor(element))
+        return;
+
     InvalidationLists invalidationLists;
     RuleFeatureSet& ruleFeatureSet = ensureResolver().ensureUpdatedRuleFeatureSet();
     if (!oldId.isEmpty())
         ruleFeatureSet.collectInvalidationSetsForId(invalidationLists, element, oldId);
     if (!newId.isEmpty())
         ruleFeatureSet.collectInvalidationSetsForId(invalidationLists, element, newId);
     m_styleInvalidator.scheduleInvalidationSetsForElement(invalidationLists, element);
 }
 
 void StyleEngine::pseudoStateChangedForElement(CSSSelector::PseudoType pseudoType, Element& element)
 {
-    ASSERT(isMaster());
+    if (shouldSkipInvalidationFor(element))
+        return;
+
     InvalidationLists invalidationLists;
     ensureResolver().ensureUpdatedRuleFeatureSet().collectInvalidationSetsForPseudoClass(invalidationLists, element, pseudoType);
     m_styleInvalidator.scheduleInvalidationSetsForElement(invalidationLists, element);
 }
 
 DEFINE_TRACE(StyleEngine)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_document);
     visitor->trace(m_injectedAuthorStyleSheets);
     visitor->trace(m_documentStyleSheetCollection);
     visitor->trace(m_styleSheetCollectionMap);
     visitor->trace(m_resolver);
     visitor->trace(m_styleInvalidator);
     visitor->trace(m_dirtyTreeScopes);
     visitor->trace(m_activeTreeScopes);
     visitor->trace(m_fontSelector);
     visitor->trace(m_textToSheetCache);
     visitor->trace(m_sheetToTextCache);
 #endif
     CSSFontSelectorClient::trace(visitor);
 }
 
 }