When there are no more stylesheets schedule the recalc async

Source/core/dom/Document.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 1586 matching lines @@
     TRACE_EVENT0("webkit", "Document::recalcStyle");
 
     // FIXME: We should update style on our ancestor chain before proceeding (especially for seamless),
     // however doing so currently causes several tests to crash, as Frame::setDocument calls Document::attach
     // before setting the DOMWindow on the Frame, or the SecurityOrigin on the document. The attach, in turn
     // resolves style (here) and then when we resolve style on the parent chain, we may end up
     // re-attaching our containing iframe, which when asked HTMLFrameElementBase::isURLAllowed
     // hits a null-dereference due to security code always assuming the document has a SecurityOrigin.
 
     if (m_styleSheetCollection->needsUpdateActiveStylesheetsOnStyleRecalc())
-        m_styleSheetCollection->updateActiveStyleSheets(DocumentStyleSheetCollection::FullUpdate);
+        m_styleSheetCollection->updateActiveStyleSheets(FullStyleUpdate);
 
     InspectorInstrumentationCookie cookie = InspectorInstrumentation::willRecalculateStyle(this);
 
     if (m_elemSheet && m_elemSheet->contents()->usesRemUnits())
         m_styleSheetCollection->setUsesRemUnit(true);
 
     m_inStyleRecalc = true;
     {
         PostAttachCallbackDisabler disabler(this);
         WidgetHierarchyUpdatesSuspensionScope suspendWidgetHierarchyUpdates;
@@ skipping 980 matching lines @@
 
 void Document::seamlessParentUpdatedStylesheets()
 {
     styleResolverChanged(RecalcStyleImmediately);
 }
 
 void Document::didRemoveAllPendingStylesheet()
 {
     m_needsNotifyRemoveAllPendingStylesheet = false;
 
-    styleResolverChanged(RecalcStyleIfNeeded);
+    styleResolverChanged(DeferRecalcStyle, OptimizedStyleUpdate);
 
     if (ScriptableDocumentParser* parser = scriptableDocumentParser())
         parser->executeScriptsWaitingForStylesheets();

[adamk, 2013/05/13 20:48:37]

Do you know if there are tests covering this code (might be able to find out by
commenting it out)? Our assumption is that a script depending on style recalc
will properly trigger a recalc as part of its operation, but it would be good to
verify this.

 
-    if (m_gotoAnchorNeededAfterStylesheetsLoad && view())
+    if (m_gotoAnchorNeededAfterStylesheetsLoad && view()) {
+        updateStyleIfNeeded();
         view()->scrollToFragment(m_url);
+    }
 }
 
 CSSStyleSheet* Document::elementSheet()
 {
     if (!m_elemSheet)
         m_elemSheet = CSSStyleSheet::createInline(this, m_baseURL);
     return m_elemSheet.get();
 }
 
 int Document::nodeAbsIndex(Node *node)
@@ skipping 326 matching lines @@
     m_styleSheetCollection->setSelectedStylesheetSetName(aString);
     styleResolverChanged(DeferRecalcStyle);
 }
 
 void Document::evaluateMediaQueryList()
 {
     if (m_mediaQueryMatcher)
         m_mediaQueryMatcher->styleResolverChanged();
 }
 
-void Document::styleResolverChanged(StyleResolverUpdateFlag updateFlag)
+void Document::styleResolverChanged(StyleResolverUpdateType updateType, StyleResolverUpdateMode updateMode)
 {
     // Don't bother updating, since we haven't loaded all our style info yet
     // and haven't calculated the style selector for the first time.
     if (!attached() || (!m_didCalculateStyleResolver && !haveStylesheetsLoaded())) {
         m_styleResolver.clear();
         return;
     }
     m_didCalculateStyleResolver = true;
 
 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("Beginning update of style selector at time %d.\n", elapsedTime());
 #endif
 
-    DocumentStyleSheetCollection::UpdateFlag styleSheetUpdate = (updateFlag == RecalcStyleIfNeeded)
-        ? DocumentStyleSheetCollection::OptimizedUpdate
-        : DocumentStyleSheetCollection::FullUpdate;
-    bool stylesheetChangeRequiresStyleRecalc = m_styleSheetCollection->updateActiveStyleSheets(styleSheetUpdate);
-
-    if (updateFlag == DeferRecalcStyle) {
-        scheduleForcedStyleRecalc();
-        return;
-    }
+    bool needsRecalc = m_styleSheetCollection->updateActiveStyleSheets(updateMode);
 
     if (didLayoutWithPendingStylesheets() && !m_styleSheetCollection->hasPendingSheets()) {
         m_pendingSheetLayout = IgnoreLayoutWithPendingSheets;
         if (renderer())
             renderView()->repaintViewAndCompositedLayers();
     }
 
-    if (!stylesheetChangeRequiresStyleRecalc)
+    if (!needsRecalc)
         return;
 
-    // This recalcStyle initiates a new recalc cycle. We need to bracket it to
-    // make sure animations get the correct update time
-    {
+    if (updateType >= DeferRecalcStyle)
+        scheduleForcedStyleRecalc();
+    else {
         AnimationUpdateBlock animationUpdateBlock(m_frame ? m_frame->animation() : 0);
         recalcStyle(Force);
     }
 
 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("Finished update of style selector at time %d\n", elapsedTime());
 #endif
 
     if (renderer()) {
@@ skipping 2635 matching lines @@
         return;
 
     Vector<RefPtr<Element> > associatedFormControls;
     copyToVector(m_associatedFormControls, associatedFormControls);
 
     frame()->page()->chrome()->client()->didAssociateFormControls(associatedFormControls);
     m_associatedFormControls.clear();
 }
 
 } // namespace WebCore