Bug 1214305 - Part 5: Use the secure upgraded channel URI in FetchEventRunnable::Init; r=jdm

This ensures that FetchEvent.request.url will have the correct value
for secure upgraded channels.

dom/workers/ServiceWorkerPrivate.cpp

@@ -1052,7 +1052,7 @@ public:
     NS_ENSURE_SUCCESS(rv, rv);
 
     nsCOMPtr<nsIURI> uri;
-    rv = channel->GetURI(getter_AddRefs(uri));
+    rv = mInterceptedChannel->GetSecureUpgradedChannelURI(getter_AddRefs(uri));
     NS_ENSURE_SUCCESS(rv, rv);
 
     rv = uri->GetSpec(mSpec);