Bug 1345342: Cancel pending requests. r=jya

If the pending first frame decoding was cancelled, the next call to decode could lead to a crash.

MozReview-Commit-ID: 6Q4eKUzqOly

--HG--
extra : rebase_source : 3640a2edd07fdbd4811295c0088a4086ac579b26

dom/media/platforms/wrappers/H264Converter.cpp

@@ -131,6 +131,10 @@ H264Converter::Decode(MediaRawData* aSample)
 RefPtr<MediaDataDecoder::FlushPromise>
 H264Converter::Flush()
 {
+  mDecodePromiseRequest.DisconnectIfExists();
+  mFlushRequest.DisconnectIfExists();
+  mShutdownRequest.DisconnectIfExists();
+  mDecodePromise.RejectIfExists(NS_ERROR_DOM_MEDIA_CANCELED, __func__);
   mNeedKeyframe = true;
   if (mDecoder) {
     return mDecoder->Flush();