List marker pseudo elements.

Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 52 matching lines @@
 #include "core/css/resolver/MediaQueryResult.h"
 #include "core/css/resolver/ScopedStyleResolver.h"
 #include "core/css/resolver/SharedStyleFinder.h"
 #include "core/css/resolver/StyleAdjuster.h"
 #include "core/css/resolver/StyleResolverParentScope.h"
 #include "core/css/resolver/StyleResolverState.h"
 #include "core/css/resolver/StyleResolverStats.h"
 #include "core/css/resolver/ViewportStyleResolver.h"
 #include "core/dom/CSSSelectorWatch.h"
 #include "core/dom/FirstLetterPseudoElement.h"
+#include "core/dom/MarkerPseudoElement.h"
 #include "core/dom/NodeComputedStyle.h"
 #include "core/dom/StyleEngine.h"
 #include "core/dom/Text.h"
 #include "core/dom/shadow/ElementShadow.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "core/inspector/InspectorInstrumentation.h"
@@ skipping 623 matching lines @@
 {
     if (value) {
         StyleBuilder::applyProperty(property, state, value);
         state.fontBuilder().createFont(state.document().styleEngine().fontSelector(), state.mutableStyleRef());
     }
     return CSSAnimatableValueFactory::create(property, *state.style());
 }
 
 PassRefPtrWillBeRawPtr<PseudoElement> StyleResolver::createPseudoElement(Element* parent, PseudoId pseudoId)
 {
+    if (RuntimeEnabledFeatures::listMarkerPseudoElementEnabled() && pseudoId == MARKER)
+        return MarkerPseudoElement::create(parent);

[esprehn, 2015/04/22 07:45:45]

if (pseudoId == MARKER) {
  ASSERT(RuntimeEnabledFeatures::listMarkerPseudoElementEnabled());
  return ...;
}

we should never even get here if it's disabled. Otherwise you'll return a
regular PseudoElement which is the wrong kind and that's bad.

[dsinclair, 2015/04/22 20:00:38]

Done.

     if (pseudoId == FIRST_LETTER)
         return FirstLetterPseudoElement::create(parent);
     return PseudoElement::create(parent, pseudoId);
 }
 
+bool StyleResolver::pseudoElementRequired(PseudoId pseudoId, LayoutObject& parentRenderer)

[esprehn, 2015/04/22 07:45:45]

This function doesn't use any state on |this|, it should be only in the .cpp
file and static.

[dsinclair, 2015/04/22 20:00:38]

Done.

+{
+    if (pseudoId == FIRST_LETTER)
+        return true;
+    if (RuntimeEnabledFeatures::listMarkerPseudoElementEnabled() && pseudoId == MARKER)

[esprehn, 2015/04/22 07:45:44]

I don't think you need the RuntimeEnabledFeatures flag here, we should just
never even get pseudoId == MARKER out of the system.

[dsinclair, 2015/04/22 20:00:38]

Done.

+        return true;
+    if (parentRenderer.style()->hasPseudoStyle(pseudoId))
+        return true;
+    return pseudoId >= FIRST_INTERNAL_PSEUDOID;
+}
+
 PassRefPtrWillBeRawPtr<PseudoElement> StyleResolver::createPseudoElementIfNeeded(Element& parent, PseudoId pseudoId)
 {
     LayoutObject* parentRenderer = parent.layoutObject();
     if (!parentRenderer)
         return nullptr;
 
-    // The first letter pseudo element has to look up the tree and see if any
-    // of the ancestors are first letter.
-    if (pseudoId < FIRST_INTERNAL_PSEUDOID && pseudoId != FIRST_LETTER && !parentRenderer->style()->hasPseudoStyle(pseudoId))
+    if (!pseudoElementRequired(pseudoId, *parentRenderer))
         return nullptr;
 
     if (pseudoId == BACKDROP && !parent.isInTopLayer())
         return nullptr;
 
+    // FIXME: This should also probably take inline-list-item into account when
+    // we add support.
+    if (RuntimeEnabledFeatures::listMarkerPseudoElementEnabled() && pseudoId == MARKER && parentRenderer->style()->display() != LIST_ITEM)

[esprehn, 2015/04/22 07:45:45]

ditto, no runtime check.

[dsinclair, 2015/04/22 20:00:38]

Done.

+        return nullptr;
+
     if (pseudoId == FIRST_LETTER && (parent.isSVGElement() || !FirstLetterPseudoElement::firstLetterTextRenderer(parent)))
         return nullptr;
 
     if (!canHaveGeneratedChildren(*parentRenderer))
         return nullptr;
 
     ComputedStyle* parentStyle = parentRenderer->mutableStyle();
     if (ComputedStyle* cachedStyle = parentStyle->getCachedPseudoStyle(pseudoId)) {
         if (!pseudoElementRendererIsNeeded(cachedStyle))
             return nullptr;
@@ skipping 49 matching lines @@
     // user agent rules, don't waste time walking those rules.
 
     if (!baseComputedStyle) {
         // Check UA, user and author rules.
         ElementRuleCollector collector(state.elementContext(), m_selectorFilter, state.style());
         collector.setPseudoStyleRequest(pseudoStyleRequest);
 
         matchUARules(collector);
         matchAuthorRules(state.element(), collector, false);
 
-        if (collector.matchedResult().matchedProperties.isEmpty())
+        if (!collector.matchedResult().matchedProperties.isEmpty())
+            applyMatchedProperties(state, collector.matchedResult());
+        else if (pseudoStyleRequest.pseudoId != MARKER || parentStyle->display() != LIST_ITEM)

[esprehn, 2015/04/22 07:45:45]

Can you explain this? Why is MARKER and LIST_ITEM special? You're changing the
behavior of all list items which doesn't seem right.

[dsinclair, 2015/04/22 20:00:38]

The LIST_ITEM bit was removed. The MARKER bit is required because it's possible
we're in here for a MARKER and there is no stylesheet entry. We still need to
return a style for the MARKER as it's based off the parent style.

             return false;
 
-        applyMatchedProperties(state, collector.matchedResult());
         applyCallbackSelectors(state);
 
         // Cache our original display.
         state.style()->setOriginalDisplay(state.style()->display());
 
         // FIXME: Passing 0 as the Element* introduces a lot of complexity
         // in the adjustComputedStyle code.
         adjustComputedStyle(state, 0);
 
         if (elementAnimations)
@@ skipping 687 matching lines @@
     visitor->trace(m_watchedSelectorsRules);
     visitor->trace(m_treeBoundaryCrossingRules);
     visitor->trace(m_styleResourceLoader);
     visitor->trace(m_styleSharingLists);
     visitor->trace(m_pendingStyleSheets);
     visitor->trace(m_document);
 #endif
 }
 
 } // namespace blink