List marker pseudo elements.

Source/core/css/resolver/StyleResolver.cpp

Index: Source/core/css/resolver/StyleResolver.cpp
diff --git a/Source/core/css/resolver/StyleResolver.cpp b/Source/core/css/resolver/StyleResolver.cpp
index 67b90d34bce5e301c130635d50d4fa46e0c24e9c..ab8be175e07647986add26323f38da5c425e683d 100644
--- a/Source/core/css/resolver/StyleResolver.cpp
+++ b/Source/core/css/resolver/StyleResolver.cpp
@@ -70,6 +70,7 @@
 #include "core/css/resolver/ViewportStyleResolver.h"
 #include "core/dom/CSSSelectorWatch.h"
 #include "core/dom/FirstLetterPseudoElement.h"
+#include "core/dom/MarkerPseudoElement.h"
 #include "core/dom/NodeRenderStyle.h"
 #include "core/dom/StyleEngine.h"
 #include "core/dom/Text.h"
@@ -720,25 +721,41 @@ PassRefPtrWillBeRawPtr<AnimatableValue> StyleResolver::createAnimatableValueSnap
 
 PassRefPtrWillBeRawPtr<PseudoElement> StyleResolver::createPseudoElement(Element* parent, PseudoId pseudoId)
 {
+    if (RuntimeEnabledFeatures::listMarkerPseudoElementEnabled() && pseudoId == MARKER)
+        return MarkerPseudoElement::create(parent);
     if (pseudoId == FIRST_LETTER)
         return FirstLetterPseudoElement::create(parent);
     return PseudoElement::create(parent, pseudoId);
 }
 
+bool StyleResolver::pseudoElementRequired(PseudoId pseudoId, RenderObject& parentRenderer)
+{
+    if (pseudoId == FIRST_LETTER)
+        return true;
+    if (RuntimeEnabledFeatures::listMarkerPseudoElementEnabled() && pseudoId == MARKER)
+        return true;
+    if (parentRenderer.style()->hasPseudoStyle(pseudoId))
+        return true;
+    return pseudoId >= FIRST_INTERNAL_PSEUDOID;
+}
+
 PassRefPtrWillBeRawPtr<PseudoElement> StyleResolver::createPseudoElementIfNeeded(Element& parent, PseudoId pseudoId)
 {
     RenderObject* parentRenderer = parent.renderer();
     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)

[Julien - ping for review, 2015/02/04 01:56:33]

pseudoId == MARKER && parentRenderer->style()->display() != LIST_ITEM is
repeated 3 times, we need a function to share the code.

[dsinclair, 2015/02/04 15:30:59]

They're slightly different. This one is == && != and the other one on is != ||
!=

+        return nullptr;
+
     if (pseudoId == FIRST_LETTER && (parent.isSVGElement() || !FirstLetterPseudoElement::firstLetterTextRenderer(parent)))
         return nullptr;
 
@@ -808,10 +825,11 @@ bool StyleResolver::pseudoStyleForElementInternal(Element& element, const Pseudo
         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)

[Julien - ping for review, 2015/02/04 01:56:33]

This code is pretty confusing now IMHO. Keeping the old logic (with an
_unconditional_ applyMatchedProperties called).

[dsinclair, 2015/02/04 04:41:33]

Not sure what you mean, do you mean keeping the old logic with the unconditional
applyCallbackSelectors?

The applyCallbackSelectors will only be called in the MARKER or LIST_ITEM case
at the moment. If it isn't a marker then we will return as we did previously.

             return false;
 
-        applyMatchedProperties(state, collector.matchedResult());
         applyCallbackSelectors(state);
 
         // Cache our original display.