Instead of signaling an inter layer dependency with the inter_layer_prediction flag we instead flatten the frame IDs so that an inter layer dependency can be signaled as a regular frame reference.
Bug: webrtc:12206, webrtc:12221
Change-Id: I0390fd3d0f5494cde59eece227db938dbc5d7992
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/196648
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32808}