Bug 1137250 - Fix incorrect initialization of Request object. r=bz

dom/bindings/BindingUtils.h

@@ -1941,15 +1941,15 @@ struct FakeString {
     return reinterpret_cast<const nsString*>(this);
   }
 
-  nsAString* ToAStringPtr() {
-    return reinterpret_cast<nsString*>(this);
-  }
-
-  operator const nsAString& () const {
+operator const nsAString& () const {
     return *reinterpret_cast<const nsString*>(this);
   }
 
 private:
+  nsAString* ToAStringPtr() {
+    return reinterpret_cast<nsString*>(this);
+  }
+
   nsString::char_type* mData;
   nsString::size_type mLength;
   uint32_t mFlags;
@@ -1965,6 +1965,8 @@ private:
     mData = const_cast<nsString::char_type*>(aData);
   }
 
+  friend class NonNull<nsAString>;
+
   // A class to use for our static asserts to ensure our object layout
   // matches that of nsString.
   class StringAsserter;

dom/workers/ServiceWorkerManager.cpp

@@ -2229,8 +2229,9 @@ private:
     MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
     GlobalObject globalObj(aCx, aWorkerPrivate->GlobalScope()->GetWrapper());
 
+    NS_ConvertUTF8toUTF16 local(mSpec);
     RequestOrUSVString requestInfo;
-    *requestInfo.SetAsUSVString().ToAStringPtr() = NS_ConvertUTF8toUTF16(mSpec);
+    requestInfo.SetAsUSVString().Rebind(local.Data(), local.Length());
 
     RootedDictionary<RequestInit> reqInit(aCx);
     reqInit.mMethod.Construct(mMethod);