List marker pseudo elements.

Source/core/layout/LayoutObject.cpp

Index: Source/core/layout/LayoutObject.cpp
diff --git a/Source/core/layout/LayoutObject.cpp b/Source/core/layout/LayoutObject.cpp
index 2a53e6c0bcf239ece950374033a7d277288384c1..d8fd87c719a3f04c0fc211c3fc7aea7e709e5c3f 100644
--- a/Source/core/layout/LayoutObject.cpp
+++ b/Source/core/layout/LayoutObject.cpp
@@ -1546,7 +1546,8 @@ void LayoutObject::showLayoutObject() const
 
 void LayoutObject::showLayoutObject(int printedCharacters) const
 {
-    printedCharacters += fprintf(stderr, "%s %p", decoratedName().ascii().data(), this);
+    IntRect size = absoluteBoundingBoxRect();
+    printedCharacters += fprintf(stderr, "%s %p (%d,%d %dx%d)", decoratedName().ascii().data(), this, size.x(), size.y(), size.width(), size.height());
 
     if (isText() && toLayoutText(this)->isTextFragment())
         printedCharacters += fprintf(stderr, " \"%s\" ", toLayoutText(this)->text().ascii().data());
@@ -1556,6 +1557,7 @@ void LayoutObject::showLayoutObject(int printedCharacters) const
             for (; printedCharacters < showTreeCharacterOffset; printedCharacters++)
                 fputc(' ', stderr);
         fputc('\t', stderr);
+        fputc('\t', stderr);
         node()->showNode();
     } else {
         fputc('\n', stderr);
@@ -1703,7 +1705,8 @@ StyleDifference LayoutObject::adjustStyleDifference(StyleDifference diff) const
 
 void LayoutObject::setPseudoStyle(PassRefPtr<ComputedStyle> pseudoStyle)
 {
-    ASSERT(pseudoStyle->styleType() == BEFORE || pseudoStyle->styleType() == AFTER || pseudoStyle->styleType() == FIRST_LETTER);
+    ASSERT(pseudoStyle->styleType() == BEFORE || pseudoStyle->styleType() == AFTER || pseudoStyle->styleType() == FIRST_LETTER
+        || (RuntimeEnabledFeatures::listMarkerPseudoElementEnabled() && pseudoStyle->styleType() == MARKER));
 
     // FIXME: We should consider just making all pseudo items use an inherited style.