--- a/widget/windows/JumpListItem.cpp
+++ b/widget/windows/JumpListItem.cpp
@@ -21,43 +21,51 @@
 
 namespace mozilla {
 namespace widget {
 
 // ISUPPORTS Impl's
 NS_IMPL_ISUPPORTS(JumpListItem,
                   nsIJumpListItem)
 
-NS_IMPL_ISUPPORTS_INHERITED(JumpListSeparator,
-                            JumpListItem,
-                            nsIJumpListSeparator)
+NS_INTERFACE_MAP_BEGIN(JumpListSeparator)
+  NS_INTERFACE_MAP_ENTRY(nsIJumpListSeparator)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsIJumpListItem, JumpListItemBase)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, JumpListItemBase)
+NS_INTERFACE_MAP_END
+NS_IMPL_ADDREF(JumpListSeparator)
+NS_IMPL_RELEASE(JumpListSeparator)
 
-NS_IMPL_ISUPPORTS_INHERITED(JumpListLink,
-                            JumpListItem,
-                            nsIJumpListLink)
+NS_INTERFACE_MAP_BEGIN(JumpListLink)
+  NS_INTERFACE_MAP_ENTRY(nsIJumpListLink)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsIJumpListItem, JumpListItemBase)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, JumpListItemBase)
+NS_INTERFACE_MAP_END
+NS_IMPL_ADDREF(JumpListLink)
+NS_IMPL_RELEASE(JumpListLink)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(JumpListShortcut)
   NS_INTERFACE_MAP_ENTRY(nsIJumpListShortcut)
-NS_INTERFACE_MAP_END_INHERITING(JumpListItem)
-
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsIJumpListItem, JumpListItemBase)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIJumpListShortcut)
+NS_INTERFACE_MAP_END
+NS_IMPL_CYCLE_COLLECTING_ADDREF(JumpListShortcut)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(JumpListShortcut)
 NS_IMPL_CYCLE_COLLECTION(JumpListShortcut, mHandlerApp)
 
-NS_IMPL_CYCLE_COLLECTING_ADDREF(JumpListShortcut)
-NS_IMPL_CYCLE_COLLECTING_RELEASE(JumpListShortcut)
-
-NS_IMETHODIMP JumpListItem::GetType(int16_t *aType)
+NS_IMETHODIMP JumpListItemBase::GetType(int16_t *aType)
 {
   NS_ENSURE_ARG_POINTER(aType);
 
   *aType = mItemType;
 
   return NS_OK;
 }
 
-NS_IMETHODIMP JumpListItem::Equals(nsIJumpListItem *aItem, bool *aResult)
+NS_IMETHODIMP JumpListItemBase::Equals(nsIJumpListItem *aItem, bool *aResult)
 {
   NS_ENSURE_ARG_POINTER(aItem);
 
   *aResult = false;
 
   int16_t theType = nsIJumpListItem::JUMPLIST_ITEM_EMPTY;
   if (NS_FAILED(aItem->GetType(&theType)))
     return NS_OK;

--- a/widget/windows/JumpListItem.h
+++ b/widget/windows/JumpListItem.h
@@ -21,92 +21,100 @@
 #include "nsString.h"
 #include "nsCycleCollectionParticipant.h"
 
 class nsIThread;
 
 namespace mozilla {
 namespace widget {
 
-class JumpListItem : public nsIJumpListItem
+class JumpListItemBase : public nsIJumpListItem
 {
 public:
-  JumpListItem() :
+  JumpListItemBase() :
    mItemType(nsIJumpListItem::JUMPLIST_ITEM_EMPTY)
   {}
 
-  JumpListItem(int32_t type) :
+  JumpListItemBase(int32_t type) :
    mItemType(type)
   {}
 
-  NS_DECL_ISUPPORTS
   NS_DECL_NSIJUMPLISTITEM
 
   static const char kJumpListCacheDir[];
 
 protected:
-  virtual ~JumpListItem()
+  virtual ~JumpListItemBase()
   {}
 
   short Type() { return mItemType; }
   short mItemType;
 
 };
 
-class JumpListSeparator : public JumpListItem, public nsIJumpListSeparator
+class JumpListItem : public JumpListItemBase
+{
+  ~JumpListItem() {}
+
+public:
+  using JumpListItemBase::JumpListItemBase;
+
+  NS_DECL_ISUPPORTS
+};
+
+class JumpListSeparator : public JumpListItemBase, public nsIJumpListSeparator
 {
   ~JumpListSeparator() {}
 
 public:
   JumpListSeparator() :
-   JumpListItem(nsIJumpListItem::JUMPLIST_ITEM_SEPARATOR)
+   JumpListItemBase(nsIJumpListItem::JUMPLIST_ITEM_SEPARATOR)
   {}
 
-  NS_DECL_ISUPPORTS_INHERITED
-  NS_IMETHOD GetType(int16_t *aType) override { return JumpListItem::GetType(aType); }
-  NS_IMETHOD Equals(nsIJumpListItem *item, bool *_retval) override { return JumpListItem::Equals(item, _retval); }
+  NS_DECL_ISUPPORTS
+  NS_FORWARD_NSIJUMPLISTITEM(JumpListItemBase::)
 
   static nsresult GetSeparator(RefPtr<IShellLinkW>& aShellLink);
 };
 
-class JumpListLink : public JumpListItem, public nsIJumpListLink
+class JumpListLink : public JumpListItemBase, public nsIJumpListLink
 {
   ~JumpListLink() {}
 
 public:
   JumpListLink() :
-   JumpListItem(nsIJumpListItem::JUMPLIST_ITEM_LINK)
+   JumpListItemBase(nsIJumpListItem::JUMPLIST_ITEM_LINK)
   {}
 
-  NS_DECL_ISUPPORTS_INHERITED
-  NS_IMETHOD GetType(int16_t *aType) override { return JumpListItem::GetType(aType); }
+  NS_DECL_ISUPPORTS
+  NS_IMETHOD GetType(int16_t *aType) override { return JumpListItemBase::GetType(aType); }
   NS_IMETHOD Equals(nsIJumpListItem *item, bool *_retval) override;
   NS_DECL_NSIJUMPLISTLINK
 
   static nsresult GetShellItem(nsCOMPtr<nsIJumpListItem>& item, RefPtr<IShellItem2>& aShellItem);
   static nsresult GetJumpListLink(IShellItem *pItem, nsCOMPtr<nsIJumpListLink>& aLink);
 
 protected:
   nsString mUriTitle;
   nsCOMPtr<nsIURI> mURI;
   nsCOMPtr<nsICryptoHash> mCryptoHash;
 };
 
-class JumpListShortcut : public JumpListItem, public nsIJumpListShortcut
+class JumpListShortcut : public JumpListItemBase, public nsIJumpListShortcut
 {
   ~JumpListShortcut() {}
 
 public:
   JumpListShortcut() :
-   JumpListItem(nsIJumpListItem::JUMPLIST_ITEM_SHORTCUT)
+   JumpListItemBase(nsIJumpListItem::JUMPLIST_ITEM_SHORTCUT)
   {}
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(JumpListShortcut, JumpListItem)
-  NS_IMETHOD GetType(int16_t *aType) override { return JumpListItem::GetType(aType); }
+  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(JumpListShortcut, JumpListItemBase)
+  NS_IMETHOD GetType(int16_t *aType) override { return JumpListItemBase::GetType(aType); }
   NS_IMETHOD Equals(nsIJumpListItem *item, bool *_retval) override;
   NS_DECL_NSIJUMPLISTSHORTCUT
 
   static nsresult GetShellLink(nsCOMPtr<nsIJumpListItem>& item,
                                RefPtr<IShellLinkW>& aShellLink,
                                nsCOMPtr<nsIThread> &aIOThread);
   static nsresult GetJumpListShortcut(IShellLinkW *pLink, nsCOMPtr<nsIJumpListShortcut>& aShortcut);
   static nsresult GetOutputIconPath(nsCOMPtr<nsIURI> aFaviconPageURI,