Bug 1396643: Fix compilation when warning as error is set. r=cpearce

MozReview-Commit-ID: Ar2Ttk5hkGD

--HG--
extra : rebase_source : 6ebcafbbb3509b8f10f3173092cdead5cbcadfc6

dom/media/ipc/RemoteVideoDecoder.cpp

@@ -67,7 +67,7 @@ RemoteVideoDecoder::Init()
              mConversion = mActor->NeedsConversion();
              return InitPromise::CreateAndResolve(aTrack, __func__);
            },
-           [self, this](const MediaResult& aError) {
+           [self](const MediaResult& aError) {
              return InitPromise::CreateAndReject(aError, __func__);
            });
 }