diff --git a/content/base/public/nsIAttribute.h b/content/base/public/nsIAttribute.h
index f27272d00e52..7c6a449dd28a 100644
--- a/content/base/public/nsIAttribute.h
+++ b/content/base/public/nsIAttribute.h
@@ -12,8 +12,8 @@ class nsDOMAttributeMap;
 class nsIContent;
 
 #define NS_IATTRIBUTE_IID  \
-{ 0x8d9d7dbf, 0xc42d, 0x4715, \
-  { 0x95, 0xcf, 0x7a, 0x5e, 0xd5, 0xa4, 0x47, 0x70 } }
+{ 0x727dc139, 0xf516, 0x46ff, \
+  { 0x86, 0x11, 0x18, 0xea, 0xee, 0x4a, 0x3e, 0x6a } }
 
 class nsIAttribute : public nsINode
 {
@@ -32,8 +32,6 @@ public:
     return mNodeInfo;
   }
 
-  virtual nsIContent* GetContent() const = 0;
-
   /**
    * Called when our ownerElement is moved into a new document.
    * Updates the nodeinfo of this node.
diff --git a/content/base/src/Attr.cpp b/content/base/src/Attr.cpp
index d33ae6994a0f..da99faed6173 100644
--- a/content/base/src/Attr.cpp
+++ b/content/base/src/Attr.cpp
@@ -77,7 +77,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Attr)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 
 NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN(Attr)
-  Element* ownerElement = tmp->GetContentInternal();
+  Element* ownerElement = tmp->GetElement();
   if (tmp->IsBlack()) {
     if (ownerElement) {
       // The attribute owns the element via attribute map so we can
@@ -128,16 +128,10 @@ Attr::SetMap(nsDOMAttributeMap *aMap)
   mAttrMap = aMap;
 }
 
-nsIContent*
-Attr::GetContent() const
-{
-  return GetContentInternal();
-}
-
 Element*
 Attr::GetElement() const
 {
-  nsIContent* content = GetContent();
+  nsIContent* content = mAttrMap ? mAttrMap->GetContent() : nullptr;
   return content ? content->AsElement() : nullptr;
 }
 
@@ -188,7 +182,7 @@ Attr::GetNameAtom(nsIContent* aContent)
 NS_IMETHODIMP
 Attr::GetValue(nsAString& aValue)
 {
-  nsIContent* content = GetContentInternal();
+  nsIContent* content = GetElement();
   if (content) {
     nsCOMPtr<nsIAtom> nameAtom = GetNameAtom(content);
     content->GetAttr(mNodeInfo->NamespaceID(), nameAtom, aValue);
@@ -203,7 +197,7 @@ Attr::GetValue(nsAString& aValue)
 void
 Attr::SetValue(const nsAString& aValue, ErrorResult& aRv)
 {
-  nsIContent* content = GetContentInternal();
+  nsIContent* content = GetElement();
   if (!content) {
     mValue = aValue;
     return;
@@ -276,7 +270,7 @@ Attr::Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const
 already_AddRefed<nsIURI>
 Attr::GetBaseURI() const
 {
-  nsINode *parent = GetContentInternal();
+  nsINode *parent = GetElement();
 
   return parent ? parent->GetBaseURI() : nullptr;
 }
@@ -301,7 +295,7 @@ Attr::SetTextContentInternal(const nsAString& aTextContent,
 NS_IMETHODIMP
 Attr::GetIsId(bool* aReturn)
 {
-  nsIContent* content = GetContentInternal();
+  nsIContent* content = GetElement();
   if (!content)
   {
     *aReturn = false;
@@ -387,11 +381,5 @@ Attr::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aScope)
   return AttrBinding::Wrap(aCx, aScope, this);
 }
 
-Element*
-Attr::GetContentInternal() const
-{
-  return mAttrMap ? mAttrMap->GetContent() : nullptr;
-}
-
 } // namespace dom
 } // namespace mozilla
diff --git a/content/base/src/Attr.h b/content/base/src/Attr.h
index eb0d46d4de53..a65f5d7e8a4c 100644
--- a/content/base/src/Attr.h
+++ b/content/base/src/Attr.h
@@ -54,7 +54,6 @@ public:
 
   // nsIAttribute interface
   void SetMap(nsDOMAttributeMap *aMap) MOZ_OVERRIDE;
-  nsIContent *GetContent() const MOZ_OVERRIDE;
   Element *GetElement() const;
   nsresult SetOwnerDocument(nsIDocument* aDocument) MOZ_OVERRIDE;
 
@@ -96,14 +95,13 @@ public:
 protected:
   virtual Element* GetNameSpaceElement()
   {
-    return GetContentInternal();
+    return GetElement();
   }
 
   static bool sInitialized;
 
 private:
   already_AddRefed<nsIAtom> GetNameAtom(nsIContent* aContent);
-  Element* GetContentInternal() const;
 
   nsString mValue;
 };
diff --git a/content/base/src/nsINode.cpp b/content/base/src/nsINode.cpp
index d4aeedd88abf..7825d2e7aa07 100644
--- a/content/base/src/nsINode.cpp
+++ b/content/base/src/nsINode.cpp
@@ -774,10 +774,10 @@ nsINode::CompareDocumentPosition(nsINode& aOtherNode) const
   const nsINode *node1 = &aOtherNode, *node2 = this;
 
   // Check if either node is an attribute
-  const nsIAttribute* attr1 = nullptr;
+  const Attr* attr1 = nullptr;
   if (node1->IsNodeOfType(nsINode::eATTRIBUTE)) {
-    attr1 = static_cast<const nsIAttribute*>(node1);
-    const nsIContent* elem = attr1->GetContent();
+    attr1 = static_cast<const Attr*>(node1);
+    const nsIContent* elem = attr1->GetElement();
     // If there is an owner element add the attribute
     // to the chain and walk up to the element
     if (elem) {
@@ -786,8 +786,8 @@ nsINode::CompareDocumentPosition(nsINode& aOtherNode) const
     }
   }
   if (node2->IsNodeOfType(nsINode::eATTRIBUTE)) {
-    const nsIAttribute* attr2 = static_cast<const nsIAttribute*>(node2);
-    const nsIContent* elem = attr2->GetContent();
+    const Attr* attr2 = static_cast<const Attr*>(node2);
+    const nsIContent* elem = attr2->GetElement();
     if (elem == node1 && attr1) {
       // Both nodes are attributes on the same element.
       // Compare position between the attributes.
diff --git a/dom/xslt/xpath/nsXPathResult.cpp b/dom/xslt/xpath/nsXPathResult.cpp
index 0c7acb1c1ad1..bf195a3eb67d 100644
--- a/dom/xslt/xpath/nsXPathResult.cpp
+++ b/dom/xslt/xpath/nsXPathResult.cpp
@@ -7,8 +7,8 @@
 #include "txExprResult.h"
 #include "txNodeSet.h"
 #include "nsError.h"
+#include "mozilla/dom/Attr.h"
 #include "mozilla/dom/Element.h"
-#include "nsIAttribute.h"
 #include "nsDOMClassInfoID.h"
 #include "nsIDOMNode.h"
 #include "nsIDOMDocument.h"
@@ -362,7 +362,7 @@ nsXPathResult::Invalidate(const nsIContent* aChangeRoot)
                     ->GetBindingParent();
         } else if (contextNode->IsNodeOfType(nsINode::eATTRIBUTE)) {
             nsIContent* parent =
-              static_cast<nsIAttribute*>(contextNode.get())->GetContent();
+              static_cast<Attr*>(contextNode.get())->GetElement();
             if (parent) {
                 ctxBindingParent = parent->GetBindingParent();
             }
diff --git a/dom/xslt/xpath/txMozillaXPathTreeWalker.cpp b/dom/xslt/xpath/txMozillaXPathTreeWalker.cpp
index 94b1aac1cea9..c41d615e3aba 100644
--- a/dom/xslt/xpath/txMozillaXPathTreeWalker.cpp
+++ b/dom/xslt/xpath/txMozillaXPathTreeWalker.cpp
@@ -21,10 +21,13 @@
 #include "nsUnicharUtils.h"
 #include "nsAttrName.h"
 #include "nsTArray.h"
+#include "mozilla/dom/Attr.h"
 #include "mozilla/dom/Element.h"
 #include <stdint.h>
 #include <algorithm>
 
+using mozilla::dom::Attr;
+
 const uint32_t kUnknownIndex = uint32_t(-1);
 
 txXPathTreeWalker::txXPathTreeWalker(const txXPathTreeWalker& aOther)
@@ -690,7 +693,7 @@ txXPathNativeNode::createXPathNode(nsIDOMNode* aNode, bool aKeepRootAlive)
         NS_ASSERTION(attr, "doesn't implement nsIAttribute");
 
         nsINodeInfo *nodeInfo = attr->NodeInfo();
-        nsIContent *parent = attr->GetContent();
+        nsIContent *parent = static_cast<Attr*>(attr.get())->GetElement();
         if (!parent) {
             return nullptr;
         }