[No issue] Hold some strong references on nsRefreshDriver

dom/base/nsDOMWindowUtils.cpp

@@ -2409,7 +2409,7 @@ nsDOMWindowUtils::AdvanceTimeAndRefresh(int64_t aMilliseconds)
 
   nsPresContext* presContext = GetPresContext();
   if (presContext) {
-    nsRefreshDriver* driver = presContext->RefreshDriver();
+    RefPtr<nsRefreshDriver> driver = presContext->RefreshDriver();
     driver->AdvanceTimeAndRefresh(aMilliseconds);
 
     RefPtr<LayerTransactionChild> transaction = GetLayerTransaction();

image/SVGDocumentWrapper.cpp

@@ -212,9 +212,12 @@ SVGDocumentWrapper::TickRefreshDriver()
   nsCOMPtr<nsIPresShell> presShell;
   mViewer->GetPresShell(getter_AddRefs(presShell));
   if (presShell) {
-    nsPresContext* presContext = presShell->GetPresContext();
+    RefPtr<nsPresContext> presContext = presShell->GetPresContext();
     if (presContext) {
-      presContext->RefreshDriver()->DoTick();
+      RefPtr<nsRefreshDriver> driver = presContext->RefreshDriver();
+      if (driver) {
+        driver->DoTick();
+      }
     }
   }
 }