Don't update internal state of the FrameBuffer2 when an undecodable frame is inserted.

Bug: chromium:844313
Change-Id: I034bcb47092815695084e37c81150bafbfbc6b9c
Reviewed-on: https://webrtc-review.googlesource.com/79944
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23577}
diff --git a/modules/video_coding/frame_buffer2_unittest.cc b/modules/video_coding/frame_buffer2_unittest.cc
index 304910a..1378be5 100644
--- a/modules/video_coding/frame_buffer2_unittest.cc
+++ b/modules/video_coding/frame_buffer2_unittest.cc
@@ -592,5 +592,15 @@
   CheckFrame(1, kMaxBufferSize + 1, 0);
 }
 
+TEST_F(TestFrameBuffer2, DontUpdateOnUndecodableFrame) {
+  InsertFrame(1, 0, 0, false);
+  ExtractFrame(0, true);
+  InsertFrame(3, 0, 0, false, 2, 0);
+  InsertFrame(3, 0, 0, false, 0);
+  InsertFrame(2, 0, 0, false);
+  ExtractFrame(0, true);
+  ExtractFrame(0, true);
+}
+
 }  // namespace video_coding
 }  // namespace webrtc