Reland of quest keyframes more frequently on stream start/decoding error. (patchset #1 id:1 of https://codereview.chromium.org/2994043002/ )

Reason for revert:
Create fix CL.

Original issue's description:
> Revert of Request keyframes more frequently on stream start/decoding error. (patchset #1 id:1 of https://codereview.webrtc.org/2993793002/ )
>
> Reason for revert:
> Broke downstream test that was waiting for 5 keyframes to be received within 10 seconds. Maybe the issue is that "stats_callback_->OnCompleteFrame(frame->num_references == 0, ..." was changed to "frame->is_keyframe()"?
>
> Original issue's description:
> > Request keyframes more frequently on stream start/decoding error.
> >
> > In this CL:
> >  - Added FrameObject::is_keyframe() convinience function.
> >  - Moved logic to request keyframes on decoding error from VideoReceived to
> >    VideoReceiveStream.
> >  - Added keyframe_required as a parameter to FrameBuffer::NextFrame.
> >
> > BUG=webrtc:8074
> >
> > Review-Url: https://codereview.webrtc.org/2993793002
> > Cr-Commit-Position: refs/heads/master@{#19280}
> > Committed: https://chromium.googlesource.com/external/webrtc/+/26b48043581735eed6e36b95fae6f5b1bcf8cfb5
>
> TBR=terelius@webrtc.org,stefan@webrtc.org,noahric@chromium.org,philipel@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:8074
>
> Review-Url: https://codereview.webrtc.org/2994043002
> Cr-Commit-Position: refs/heads/master@{#19295}
> Committed: https://chromium.googlesource.com/external/webrtc/+/77a983185f57628cd5955bd2c0a1bf71c30439bb

TBR=terelius@webrtc.org,stefan@webrtc.org,noahric@chromium.org,deadbeef@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
BUG=webrtc:8074

Review-Url: https://codereview.webrtc.org/2996823002
Cr-Commit-Position: refs/heads/master@{#19324}
diff --git a/webrtc/modules/video_coding/frame_buffer2.h b/webrtc/modules/video_coding/frame_buffer2.h
index 4950dac..8de0680 100644
--- a/webrtc/modules/video_coding/frame_buffer2.h
+++ b/webrtc/modules/video_coding/frame_buffer2.h
@@ -57,7 +57,8 @@
   //    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.