Fix hangs & crashes in teardown-during-Seek.

media/filters/ffmpeg_video_decoder.cc

Index: media/filters/ffmpeg_video_decoder.cc
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index d41b796291b5e402f5bd7c79b40aa64bd40b1d8f..d5402279f7548d75c54ba2f5516dd704e8b4ff65 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -255,8 +255,10 @@ void FFmpegVideoDecoder::OnReadCompleteTask(scoped_refptr<Buffer> buffer) {
 void FFmpegVideoDecoder::ProduceVideoFrame(
     scoped_refptr<VideoFrame> video_frame) {
   if (MessageLoop::current() != message_loop_) {
-    message_loop_->PostTask(FROM_HERE, base::Bind(
-        &FFmpegVideoDecoder::ProduceVideoFrame, this, video_frame));
+    if (state_ != kStopped) {
+      message_loop_->PostTask(FROM_HERE, base::Bind(
+          &FFmpegVideoDecoder::ProduceVideoFrame, this, video_frame));
+    }
     return;
   }