--- a/chrome/nsChromeRegistryChrome.cpp
+++ b/chrome/nsChromeRegistryChrome.cpp
@@ -676,28 +676,36 @@ nsChromeRegistryChrome::OverlayListHash:
   return &entry->mArray;
 }
 
 #ifdef MOZ_XUL
 NS_IMETHODIMP
 nsChromeRegistryChrome::GetStyleOverlays(nsIURI *aChromeURL,
                                          nsISimpleEnumerator **aResult)
 {
-  const nsCOMArray<nsIURI>* parray = mStyleHash.GetArray(aChromeURL);
+  nsCOMPtr<nsIURI> chromeURLWithoutHash;
+  if (aChromeURL) {
+    aChromeURL->CloneIgnoringRef(getter_AddRefs(chromeURLWithoutHash));
+  }
+  const nsCOMArray<nsIURI>* parray = mStyleHash.GetArray(chromeURLWithoutHash);
   if (!parray)
     return NS_NewEmptyEnumerator(aResult);
 
   return NS_NewArrayEnumerator(aResult, *parray);
 }
 
 NS_IMETHODIMP
 nsChromeRegistryChrome::GetXULOverlays(nsIURI *aChromeURL,
                                        nsISimpleEnumerator **aResult)
 {
-  const nsCOMArray<nsIURI>* parray = mOverlayHash.GetArray(aChromeURL);
+  nsCOMPtr<nsIURI> chromeURLWithoutHash;
+  if (aChromeURL) {
+    aChromeURL->CloneIgnoringRef(getter_AddRefs(chromeURLWithoutHash));
+  }
+  const nsCOMArray<nsIURI>* parray = mOverlayHash.GetArray(chromeURLWithoutHash);
   if (!parray)
     return NS_NewEmptyEnumerator(aResult);
 
   return NS_NewArrayEnumerator(aResult, *parray);
 }
 #endif // MOZ_XUL
 
 nsIURI*
@@ -890,17 +898,20 @@ nsChromeRegistryChrome::ManifestOverlay(
   }
 
   if (!CanLoadResource(overlayuri)) {
     LogMessageWithContext(cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
                           "Cannot register non-local URI '%s' as an overlay.", overlay);
     return;
   }
 
-  mOverlayHash.Add(baseuri, overlayuri);
+  nsCOMPtr<nsIURI> baseuriWithoutHash;
+  baseuri->CloneIgnoringRef(getter_AddRefs(baseuriWithoutHash));
+
+  mOverlayHash.Add(baseuriWithoutHash, overlayuri);
 }
 
 void
 nsChromeRegistryChrome::ManifestStyle(ManifestProcessingContext& cx, int lineno,
                                       char *const * argv, bool platform,
                                       bool contentaccessible)
 {
   char* base = argv[0];
@@ -915,17 +926,20 @@ nsChromeRegistryChrome::ManifestStyle(Ma
   }
 
   if (!CanLoadResource(overlayuri)) {
     LogMessageWithContext(cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
                           "Cannot register non-local URI '%s' as a style overlay.", overlay);
     return;
   }
 
-  mStyleHash.Add(baseuri, overlayuri);
+  nsCOMPtr<nsIURI> baseuriWithoutHash;
+  baseuri->CloneIgnoringRef(getter_AddRefs(baseuriWithoutHash));
+
+  mStyleHash.Add(baseuriWithoutHash, overlayuri);
 }
 
 void
 nsChromeRegistryChrome::ManifestOverride(ManifestProcessingContext& cx, int lineno,
                                          char *const * argv, bool platform,
                                          bool contentaccessible)
 {
   char* chrome = argv[0];

--- a/content/xul/document/src/nsXULPrototypeCache.cpp
+++ b/content/xul/document/src/nsXULPrototypeCache.cpp
@@ -126,17 +126,23 @@ nsXULPrototypeCache::Observe(nsISupports
         NS_WARNING("Unexpected observer topic.");
     }
     return NS_OK;
 }
 
 nsXULPrototypeDocument*
 nsXULPrototypeCache::GetPrototype(nsIURI* aURI)
 {
-    nsXULPrototypeDocument* protoDoc = mPrototypeTable.GetWeak(aURI);
+    if (!aURI)
+        return nullptr;
+
+    nsCOMPtr<nsIURI> uriWithoutRef;
+    aURI->CloneIgnoringRef(getter_AddRefs(uriWithoutRef));
+
+    nsXULPrototypeDocument* protoDoc = mPrototypeTable.GetWeak(uriWithoutRef);
     if (protoDoc)
         return protoDoc;
 
     nsresult rv = BeginCaching(aURI);
     if (NS_FAILED(rv))
         return nullptr;
 
     // No prototype in XUL memory cache. Spin up the cache Service.
@@ -159,17 +165,23 @@ nsXULPrototypeCache::GetPrototype(nsIURI
     
     mInputStreamTable.Remove(aURI);
     return newProto;
 }
 
 nsresult
 nsXULPrototypeCache::PutPrototype(nsXULPrototypeDocument* aDocument)
 {
-    nsCOMPtr<nsIURI> uri = aDocument->GetURI();
+    if (!aDocument->GetURI()) {
+        return NS_ERROR_FAILURE;
+    }
+
+    nsCOMPtr<nsIURI> uri;
+    aDocument->GetURI()->CloneIgnoringRef(getter_AddRefs(uri));
+
     // Put() releases any old value and addrefs the new one
     mPrototypeTable.Put(uri, aDocument);
 
     return NS_OK;
 }
 
 nsresult
 nsXULPrototypeCache::PutStyleSheet(CSSStyleSheet* aStyleSheet)