Bug 1423492 part 3. Stop overring UnsetAttr in SVGMarkerElement. r=bytesized,qdot

This changes behavior some, by moving the code involved from "before we remove
the attribute" to AfterSetAttr.  But I think it should be OK, and SVG elements
can't sanely implement BeforeSetAttr right now...

MozReview-Commit-ID: KQGIDQOMGne

dom/svg/SVGMarkerElement.cpp

@@ -237,16 +237,21 @@ SVGMarkerElement::ParseAttribute(int32_t aNameSpaceID, nsAtom* aName,
 }
 
 nsresult
-SVGMarkerElement::UnsetAttr(int32_t aNamespaceID, nsAtom* aName,
-                            bool aNotify)
+SVGMarkerElement::AfterSetAttr(int32_t aNamespaceID, nsAtom* aName,
+                                const nsAttrValue* aValue,
+                                const nsAttrValue* aOldValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
+                                bool aNotify)
 {
-  if (aNamespaceID == kNameSpaceID_None) {
-    if (aName == nsGkAtoms::orient) {
-      mOrientType.SetBaseValue(SVG_MARKER_ORIENT_ANGLE);
-    }
+  if (!aValue && aNamespaceID == kNameSpaceID_None &&
+      aName == nsGkAtoms::orient) {
+    mOrientType.SetBaseValue(SVG_MARKER_ORIENT_ANGLE);
   }
 
-  return nsSVGElement::UnsetAttr(aNamespaceID, aName, aNotify);
+  return SVGMarkerElementBase::AfterSetAttr(aNamespaceID, aName,
+                                            aValue, aOldValue,
+                                            aMaybeScriptedPrincipal,
+                                            aNotify);
 }
 
 //----------------------------------------------------------------------

dom/svg/SVGMarkerElement.h

@@ -115,8 +115,11 @@ public:
   // nsIContent interface
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* name) const override;
 
-  virtual nsresult UnsetAttr(int32_t aNameSpaceID, nsAtom* aAttribute,
-                             bool aNotify) override;
+  virtual nsresult AfterSetAttr(int32_t aNamespaceID, nsAtom* aName,
+                                const nsAttrValue* aValue,
+                                const nsAttrValue* aOldValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
+                                bool aNotify) override;
 
   // nsSVGSVGElement methods:
   virtual bool HasValidDimensions() const override;