Advance picture id of keyframe if the stream has been continuous without a new keyframe for a while.

webrtc/modules/video_coding/rtp_frame_reference_finder_unittest.cc

Index: webrtc/modules/video_coding/rtp_frame_reference_finder_unittest.cc
diff --git a/webrtc/modules/video_coding/rtp_frame_reference_finder_unittest.cc b/webrtc/modules/video_coding/rtp_frame_reference_finder_unittest.cc
index d67e1baafe670797c15e004add01d43a9f9390a9..5fa88802a6bb03e33d964d3c097a01b559d9d343 100644
--- a/webrtc/modules/video_coding/rtp_frame_reference_finder_unittest.cc
+++ b/webrtc/modules/video_coding/rtp_frame_reference_finder_unittest.cc
@@ -300,6 +300,19 @@ TEST_F(TestRtpFrameReferenceFinder, PaddingPacketsReorderedMultipleKeyframes) {
   EXPECT_EQ(4UL, frames_from_callback_.size());
 }
 
+TEST_F(TestRtpFrameReferenceFinder, AdvanceSavedKeyframe) {
+  uint16_t sn = Rand();

[terelius, 2017/02/20 13:19:48]

With a random sequence number you have no way of knowing if or when the sequence
number wraps, right?

[philipel, 2017/02/20 13:26:42]

That is true, but the problem only occurs when the sequence number of the last
packet of a frame is further ahead than <keyframe sequence number + 2^15>. If
the actual sequence number has wrapped or not does not matter in this case.

+
+  InsertGeneric(sn, sn, true);
+  InsertGeneric(sn + 1, sn + 1, true);
+  InsertGeneric(sn + 2, sn + 10000, false);
+  InsertGeneric(sn + 10001, sn + 20000, false);
+  InsertGeneric(sn + 20001, sn + 30000, false);
+  InsertGeneric(sn + 30001, sn + 40000, false);
+
+  EXPECT_EQ(6UL, frames_from_callback_.size());
+}
+
 TEST_F(TestRtpFrameReferenceFinder, ClearTo) {
   uint16_t sn = Rand();