Continuously request keyframes if decoding does not recover.

video/video_receive_stream.cc

Index: video/video_receive_stream.cc
diff --git a/video/video_receive_stream.cc b/video/video_receive_stream.cc
index 7de42f8a1da8dd6f1310f21c2034c655dff1a6ba..891c78e7ec7cd13f75bcc09f19896cda8ad1bc1b 100644
--- a/video/video_receive_stream.cc
+++ b/video/video_receive_stream.cc
@@ -410,16 +410,19 @@ bool VideoReceiveStream::Decode() {
   }
 
   if (frame) {
+    int64_t now_ms = clock_->TimeInMilliseconds();
     RTC_DCHECK_EQ(res, video_coding::FrameBuffer::ReturnReason::kFrameFound);
     if (video_receiver_.Decode(frame.get()) == VCM_OK) {
       keyframe_required_ = false;
       frame_decoded_ = true;
       rtp_video_stream_receiver_.FrameDecoded(frame->picture_id);
-    } else if (!keyframe_required_ || !frame_decoded_) {
+    } else if (!frame_decoded_ || !keyframe_required_ ||
+               (last_keyframe_request_ms_ + kMaxWaitForKeyFrameMs < now_ms)) {
       keyframe_required_ = true;
       // TODO(philipel): Remove this keyframe request when downstream project
       //                 has been fixed.
       RequestKeyFrame();
+      last_keyframe_request_ms_ = now_ms;
     }
   } else {
     RTC_DCHECK_EQ(res, video_coding::FrameBuffer::ReturnReason::kTimeout);