Bug 1423492 part 4. Stop overring UnsetAttr in SVGElement. r=bytesized

There are now no more overrides of UnsetAttr, so it can stop being virtual.

MozReview-Commit-ID: 4QzAKCkRfgs

dom/base/Element.h

@@ -927,9 +927,7 @@ public:
    * @param aNotify specifies whether or not the document should be
    * notified of the attribute change
    */
-  virtual nsresult UnsetAttr(int32_t aNameSpaceID,
-                             nsAtom* aAttribute,
-                             bool aNotify);
+  nsresult UnsetAttr(int32_t aNameSpaceID, nsAtom* aAttribute, bool aNotify);
 
   /**
    * Get the namespace / name / prefix of a given attribute.

dom/svg/nsSVGElement.cpp

@@ -895,11 +895,14 @@ nsSVGElement::UnsetAttrInternal(int32_t aNamespaceID, nsAtom* aName,
 }
 
 nsresult
-nsSVGElement::UnsetAttr(int32_t aNamespaceID, nsAtom* aName,
-                        bool aNotify)
+nsSVGElement::BeforeSetAttr(int32_t aNamespaceID, nsAtom* aName,
+                            const nsAttrValueOrString* aValue,
+                            bool aNotify)
 {
-  UnsetAttrInternal(aNamespaceID, aName, aNotify);
-  return nsSVGElementBase::UnsetAttr(aNamespaceID, aName, aNotify);
+  if (!aValue) {
+    UnsetAttrInternal(aNamespaceID, aName, aNotify);
+  }
+  return nsSVGElementBase::BeforeSetAttr(aNamespaceID, aName, aValue, aNotify);
 }
 
 nsChangeHint

dom/svg/nsSVGElement.h

@@ -105,9 +105,6 @@ public:
                               nsIContent* aBindingParent,
                               bool aCompileEventHandlers) override;
 
-  virtual nsresult UnsetAttr(int32_t aNameSpaceID, nsAtom* aAttribute,
-                             bool aNotify) override;
-
   virtual nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
                                               int32_t aModType) const override;
 
@@ -336,7 +333,6 @@ public:
 protected:
   virtual JSObject* WrapNode(JSContext *cx, JS::Handle<JSObject*> aGivenProto) override;
 
-#ifdef DEBUG
   // We define BeforeSetAttr here and mark it final to ensure it is NOT used
   // by SVG elements.
   // This is because we're not currently passing the correct value for aValue to
@@ -344,11 +340,7 @@ protected:
   // See the comment in nsSVGElement::WillChangeValue.
   virtual nsresult BeforeSetAttr(int32_t aNamespaceID, nsAtom* aName,
                                  const nsAttrValueOrString* aValue,
-                                 bool aNotify) override final
-  {
-    return nsSVGElementBase::BeforeSetAttr(aNamespaceID, aName, aValue, aNotify);
-  }
-#endif // DEBUG
+                                 bool aNotify) override final;
   virtual nsresult AfterSetAttr(int32_t aNamespaceID, nsAtom* aName,
                                 const nsAttrValue* aValue,
                                 const nsAttrValue* aOldValue,