Fixes two bugs when decoding with packet losses.

Disable _missingFrame bit since we can't set it correctly with FEC.

No longer return more than one decoded frame per Decode() call.
This is a work-around for a bug where the frame info map was popped more often than items were added to the map.

BUG=
TEST=

Review URL: http://webrtc-codereview.appspot.com/215001

git-svn-id: http://webrtc.googlecode.com/svn/trunk@722 4adac7df-926f-26a2-2b94-8c16560cd09d

src/modules/video_coding/main/source/timing.cc

@@ -199,7 +199,7 @@ VCMTiming::StopDecodeTimer(WebRtc_UWord32 timeStamp,
     {
         WEBRTC_TRACE(webrtc::kTraceError, webrtc::kTraceVideoCoding, VCMId(_vcmId, _timingId),
             "Codec timer error: %d", timeDiffMs);
-        return timeDiffMs;
+        assert(false);
     }
 
     if (_master)