--- a/embedding/components/webbrowserpersist/src/nsWebBrowserPersist.cpp
+++ b/embedding/components/webbrowserpersist/src/nsWebBrowserPersist.cpp
@@ -510,18 +510,17 @@ nsWebBrowserPersist::StartUpload(nsIInpu
     // NOTE: ALL data must be available in "inputstream"
     nsresult rv = uploadChannel->SetUploadStream(aInputStream, aContentType, -1);
     NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);
     rv = destChannel->AsyncOpen(this, nullptr);
     NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);
 
     // add this to the upload list
     nsCOMPtr<nsISupports> keyPtr = do_QueryInterface(destChannel);
-    nsISupportsKey key(keyPtr);
-    mUploadList.Put(&key, new UploadData(aDestinationURI));
+    mUploadList.Put(keyPtr, new UploadData(aDestinationURI));
 
     return NS_OK;
 }
 
 nsresult
 nsWebBrowserPersist::SaveGatheredURIs(nsIURI *aFileAsURI)
 {
     nsresult rv = NS_OK;
@@ -630,18 +629,17 @@ NS_IMETHODIMP nsWebBrowserPersist::OnSta
     OutputData *data = mOutputMap.Get(keyPtr);
 
     // NOTE: This code uses the channel as a hash key so it will not
     //       recognize redirected channels because the key is not the same.
     //       When that happens we remove and add the data entry to use the
     //       new channel as the hash key.
     if (!data)
     {
-        nsISupportsKey key(keyPtr);
-        UploadData *upData = (UploadData *) mUploadList.Get(&key);
+        UploadData *upData = mUploadList.Get(keyPtr);
         if (!upData)
         {
             // Redirect? Try and fixup the output table
             nsresult rv = FixRedirectedChannelEntry(channel);
             NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);
 
             // Should be able to find the data after fixup unless redirects
             // are disabled.
@@ -701,22 +699,20 @@ NS_IMETHODIMP nsWebBrowserPersist::OnSto
             SendErrorStatusChange(true, status, request, data->mFile);
 
         // This will automatically close the output stream
         mOutputMap.Remove(keyPtr);
     }
     else
     {
         // if we didn't find the data in mOutputMap, try mUploadList
-        nsISupportsKey key(keyPtr);
-        UploadData *upData = (UploadData *) mUploadList.Get(&key);
+        UploadData *upData = mUploadList.Get(keyPtr);
         if (upData)
         {
-            delete upData;
-            mUploadList.Remove(&key);
+            mUploadList.Remove(keyPtr);
         }
     }
 
     // ensure we call SaveDocuments if we:
     // 1) aren't canceling
     // 2) we haven't triggered the save (which we only want to trigger once)
     // 3) we aren't serializing (which will call it inside SerializeNextFile)
     if (mOutputMap.Count() == 0 && !mCancel && !mStartSaving && !mSerializingOutput)
@@ -921,18 +917,17 @@ NS_IMETHODIMP nsWebBrowserPersist::OnPro
     OutputData *data = mOutputMap.Get(keyPtr);
     if (data)
     {
         data->mSelfProgress = int64_t(aProgress);
         data->mSelfProgressMax = int64_t(aProgressMax);
     }
     else
     {
-        nsISupportsKey key(keyPtr);
-        UploadData *upData = (UploadData *) mUploadList.Get(&key);
+        UploadData *upData = mUploadList.Get(keyPtr);
         if (upData)
         {
             upData->mSelfProgress = int64_t(aProgress);
             upData->mSelfProgressMax = int64_t(aProgressMax);
         }
     }
 
     // Notify listener of total progress
@@ -1767,18 +1762,18 @@ nsresult nsWebBrowserPersist::SaveDocume
 }
 
 void nsWebBrowserPersist::Cleanup()
 {
     mURIMap.Enumerate(EnumCleanupURIMap, this);
     mURIMap.Reset();
     mOutputMap.EnumerateRead(EnumCleanupOutputMap, this);
     mOutputMap.Clear();
-    mUploadList.Enumerate(EnumCleanupUploadList, this);
-    mUploadList.Reset();
+    mUploadList.EnumerateRead(EnumCleanupUploadList, this);
+    mUploadList.Clear();
     uint32_t i;
     for (i = 0; i < mDocList.Length(); i++)
     {
         DocData *docData = mDocList.ElementAt(i);
         delete docData;
     }
     mDocList.Clear();
     for (i = 0; i < mCleanupList.Length(); i++)
@@ -2312,32 +2307,16 @@ nsWebBrowserPersist::EndDownload(nsresul
         CleanupLocalFiles();
     }
 
     // Cleanup the channels
     mCompleted = true;
     Cleanup();
 }
 
-/* Hack class to get access to nsISupportsKey's protected mKey member */
-class nsMyISupportsKey : public nsISupportsKey
-{
-public:
-    nsMyISupportsKey(nsISupports *key) : nsISupportsKey(key)
-    {
-    }
-
-    nsresult GetISupports(nsISupports **ret)
-    {
-        *ret = mKey;
-        NS_IF_ADDREF(mKey);
-        return NS_OK;
-    }
-};
-
 struct MOZ_STACK_CLASS FixRedirectData
 {
     nsCOMPtr<nsIChannel> mNewChannel;
     nsCOMPtr<nsIURI> mOriginalURI;
     nsCOMPtr<nsISupports> mMatchingKey;
 };
 
 nsresult
@@ -2406,17 +2385,17 @@ nsWebBrowserPersist::CalcTotalProgress()
     {
         // Total up the progress of each output stream
         mOutputMap.EnumerateRead(EnumCalcProgress, this);
     }
 
     if (mUploadList.Count() > 0)
     {
         // Total up the progress of each upload
-        mUploadList.Enumerate(EnumCalcUploadProgress, this);
+        mUploadList.EnumerateRead(EnumCalcUploadProgress, this);
     }
 
     // XXX this code seems pretty bogus and pointless
     if (mTotalCurrentProgress == 0 && mTotalMaxProgress == 0)
     {
         // No output streams so we must be complete
         mTotalCurrentProgress = 10000;
         mTotalMaxProgress = 10000;
@@ -2433,27 +2412,26 @@ nsWebBrowserPersist::EnumCalcProgress(ns
     if (fileURL)
     {
         pthis->mTotalCurrentProgress += aData->mSelfProgress;
         pthis->mTotalMaxProgress += aData->mSelfProgressMax;
     }
     return PL_DHASH_NEXT;
 }
 
-bool
-nsWebBrowserPersist::EnumCalcUploadProgress(nsHashKey *aKey, void *aData, void* closure)
+PLDHashOperator
+nsWebBrowserPersist::EnumCalcUploadProgress(nsISupports *aKey, UploadData *aData, void* aClosure)
 {
-    if (aData && closure)
+    if (aData && aClosure)
     {
-        nsWebBrowserPersist *pthis = (nsWebBrowserPersist *) closure;
-        UploadData *data = (UploadData *) aData;
-        pthis->mTotalCurrentProgress += data->mSelfProgress;
-        pthis->mTotalMaxProgress += data->mSelfProgressMax;
+        nsWebBrowserPersist *pthis = static_cast<nsWebBrowserPersist *>(aClosure);
+        pthis->mTotalCurrentProgress += aData->mSelfProgress;
+        pthis->mTotalMaxProgress += aData->mSelfProgressMax;
     }
-    return true;
+    return PL_DHASH_NEXT;
 }
 
 bool
 nsWebBrowserPersist::EnumCountURIsToPersist(nsHashKey *aKey, void *aData, void* closure)
 {
     URIData *data = (URIData *) aData;
     uint32_t *count = (uint32_t *) closure;
     if (data->mNeedsPersisting && !data->mSaved)
@@ -2531,29 +2509,25 @@ bool
 nsWebBrowserPersist::EnumCleanupURIMap(nsHashKey *aKey, void *aData, void* closure)
 {
     URIData *data = (URIData *) aData;
     delete data; // Delete data associated with key
     return true;
 }
 
 
-bool
-nsWebBrowserPersist::EnumCleanupUploadList(nsHashKey *aKey, void *aData, void* closure)
+PLDHashOperator
+nsWebBrowserPersist::EnumCleanupUploadList(nsISupports *aKey, UploadData *aData, void* aClosure)
 {
-    nsCOMPtr<nsISupports> keyPtr;
-    ((nsMyISupportsKey *) aKey)->GetISupports(getter_AddRefs(keyPtr));
-    nsCOMPtr<nsIChannel> channel = do_QueryInterface(keyPtr);
+    nsCOMPtr<nsIChannel> channel = do_QueryInterface(aKey);
     if (channel)
     {
         channel->Cancel(NS_BINDING_ABORTED);
     }
-    UploadData *data = (UploadData *) aData;
-    delete data; // Delete data associated with key
-    return true;
+    return PL_DHASH_NEXT;
 }
 
 nsresult nsWebBrowserPersist::FixupXMLStyleSheetLink(nsIDOMProcessingInstruction *aPI, const nsAString &aHref)
 {
     NS_ENSURE_ARG_POINTER(aPI);
     nsresult rv = NS_OK;
 
     nsAutoString data;

--- a/embedding/components/webbrowserpersist/src/nsWebBrowserPersist.h
+++ b/embedding/components/webbrowserpersist/src/nsWebBrowserPersist.h
@@ -31,16 +31,17 @@
 #include "nsCWebBrowserPersist.h"
 
 class nsEncoderNodeFixup;
 class nsIStorageStream;
 
 struct CleanupData;
 struct DocData;
 struct OutputData;
+struct UploadData;
 struct URIData;
 
 class nsWebBrowserPersist : public nsIInterfaceRequestor,
                             public nsIWebBrowserPersist,
                             public nsIStreamListener,
                             public nsIProgressEventSink,
                             public nsSupportsWeakReference
 {
@@ -160,20 +161,22 @@ private:
     static bool EnumPersistURIs(
         nsHashKey *aKey, void *aData, void* closure);
     static bool EnumCleanupURIMap(
         nsHashKey *aKey, void *aData, void* closure);
     static PLDHashOperator EnumCleanupOutputMap(
         nsISupports *aKey, OutputData *aData, void* aClosure);
     static bool EnumCleanupUploadList(
         nsHashKey *aKey, void *aData, void* closure);
+    static PLDHashOperator EnumCleanupUploadList(
+        nsISupports *aKey, UploadData *aData, void* aClosure);
     static PLDHashOperator EnumCalcProgress(
         nsISupports *aKey, OutputData *aData, void* aClosure);
-    static bool EnumCalcUploadProgress(
-        nsHashKey *aKey, void *aData, void* closure);
+    static PLDHashOperator EnumCalcUploadProgress(
+        nsISupports *aKey, UploadData *aData, void* aClosure);
     static PLDHashOperator EnumFixRedirect(
         nsISupports *aKey, OutputData *aData, void* aClosure);
     static bool EnumCountURIsToPersist(
         nsHashKey *aKey, void *aData, void* closure);
 
     nsCOMPtr<nsIURI>          mCurrentDataPath;
     bool                      mCurrentDataPathIsRelative;
     nsCString                 mCurrentRelativePathToData;
@@ -188,17 +191,17 @@ private:
     /**
      * Progress listener for 64-bit values; this is the same object as
      * mProgressListener, but is a member to avoid having to qi it for each
      * progress notification.
      */
     nsCOMPtr<nsIWebProgressListener2> mProgressListener2;
     nsCOMPtr<nsIProgressEventSink> mEventSink;
     nsClassHashtable<nsISupportsHashKey, OutputData> mOutputMap;
-    nsHashtable               mUploadList;
+    nsClassHashtable<nsISupportsHashKey, UploadData> mUploadList;
     nsHashtable               mURIMap;
     nsTArray<DocData*>        mDocList;
     nsTArray<CleanupData*>    mCleanupList;
     nsTArray<nsCString>       mFilenameList;
     bool                      mFirstAndOnlyUse;
     bool                      mCancel;
     bool                      mJustStartedLoading;
     bool                      mCompleted;