Bug 1369382: Don't make hard assertion that the queued sample is a keyframe. r=kaku

When seeking, we go to the first IDR prior the seek target. However, if the MP4 sample table is invalid the frame returned may not be an IDR.

It is an error for that frame to not be a keyframe, so we do want to have way to detect them through logging. Change assertion to a soft assertion for that purpose.

MozReview-Commit-ID: EMgwRo1mYMp

--HG--
extra : rebase_source : 363a7e148db166b2130a7862a49f03d419d3fe22

dom/media/fmp4/MP4Demuxer.cpp

@@ -497,8 +497,8 @@ MP4TrackDemuxer::GetSamples(int32_t aNumSamples)
   }
 
   if (mQueuedSample) {
-    MOZ_ASSERT(mQueuedSample->mKeyframe,
-               "mQueuedSample must be a keyframe");
+    NS_ASSERTION(mQueuedSample->mKeyframe,
+                 "mQueuedSample must be a keyframe");
     samples->mSamples.AppendElement(mQueuedSample);
     mQueuedSample = nullptr;
     aNumSamples--;