Bug 1355351 - Make pseudo-elements return the correct style via getComputedStyle

* Add a node property to access the ::before and ::after pseudo-elements
* Look for the frame for ::before and ::after pseudos
* Clean up pseudo-element props
* Simplify nsLayoutUtils callers, and make child iterators notice display: contents pseudos

Tag #1375

2 files changed, 26 insertions, 0 deletions

diff --git a/dom/xml/nsXMLElement.cpp b/dom/xml/nsXMLElement.cpp
index 45163a1c4..ad0314f4c 100644
--- a/dom/xml/nsXMLElement.cpp
+++ b/dom/xml/nsXMLElement.cpp
@@ -9,6 +9,7 @@
 #include "mozilla/dom/ElementInlines.h"
 #include "nsContentUtils.h" // nsAutoScriptBlocker
 
+using namespace mozilla;
 using namespace mozilla::dom;
 
 nsresult
@@ -29,4 +30,26 @@ nsXMLElement::WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto)
   return ElementBinding::Wrap(aCx, this, aGivenProto);
 }
 
+void
+nsXMLElement::UnbindFromTree(bool aDeep, bool aNullParent)
+{
+  CSSPseudoElementType pseudoType = GetPseudoElementType();
+  bool isBefore = pseudoType == CSSPseudoElementType::before;
+  nsIAtom* property = isBefore
+    ? nsGkAtoms::beforePseudoProperty : nsGkAtoms::afterPseudoProperty;
+
+  switch (pseudoType) {
+    case CSSPseudoElementType::before:
+    case CSSPseudoElementType::after: {
+      MOZ_ASSERT(GetParent());
+      MOZ_ASSERT(GetParent()->IsElement());
+      GetParent()->DeleteProperty(property);
+      break;
+    }
+    default:
+      break;
+  }
+  Element::UnbindFromTree(aDeep, aNullParent);
+}
+
 NS_IMPL_ELEMENT_CLONE(nsXMLElement)
diff --git a/dom/xml/nsXMLElement.h b/dom/xml/nsXMLElement.h
index d16b82f39..85f79970c 100644
--- a/dom/xml/nsXMLElement.h
+++ b/dom/xml/nsXMLElement.h
@@ -35,6 +35,9 @@ public:
 
   virtual nsIDOMNode* AsDOMNode() override { return this; }
 
+  virtual void UnbindFromTree(bool aDeep = true,
+                              bool aNullParent = true) override;
+
 protected:
   virtual ~nsXMLElement() {}