Request keyframes more frequently on stream start/decoding error.

webrtc/modules/video_coding/frame_buffer2.h

Index: webrtc/modules/video_coding/frame_buffer2.h
diff --git a/webrtc/modules/video_coding/frame_buffer2.h b/webrtc/modules/video_coding/frame_buffer2.h
index 307bb85b46c339d7121d0f5ea4187a9f7897d727..13dd341aaae5b91f8bdd6ef74e901e224137e264 100644
--- a/webrtc/modules/video_coding/frame_buffer2.h
+++ b/webrtc/modules/video_coding/frame_buffer2.h
@@ -57,7 +57,8 @@ class FrameBuffer {
   //    kTimeout.
   //  - If the FrameBuffer is stopped then it will return kStopped.
   ReturnReason NextFrame(int64_t max_wait_time_ms,
-                         std::unique_ptr<FrameObject>* frame_out);
+                         std::unique_ptr<FrameObject>* frame_out,
+                         bool keyframe_required = false);
 
   // Tells the FrameBuffer which protection mode that is in use. Affects
   // the frame timing.