Reland of quest keyframes more frequently on stream start/decoding error.

webrtc/modules/video_coding/frame_object.h

Index: webrtc/modules/video_coding/frame_object.h
diff --git a/webrtc/modules/video_coding/frame_object.h b/webrtc/modules/video_coding/frame_object.h
index 07510770417ef6f09a12cc0293bb32c186bab269..5299ed8152a59827fadccfd3070178ec4c12ec10 100644
--- a/webrtc/modules/video_coding/frame_object.h
+++ b/webrtc/modules/video_coding/frame_object.h
@@ -44,6 +44,8 @@ class FrameObject : public webrtc::VCMEncodedFrame {
 
   size_t size() const { return _length; }
 
+  bool is_keyframe() const { return num_references == 0; }
+
   // The tuple (|picture_id|, |spatial_layer|) uniquely identifies a frame
   // object. For codec types that don't necessarily have picture ids they
   // have to be constructed from the header data relevant to that codec.