Ignore spatial index.
Ignore spatial index.

This workaround allows to decode VP9 SVC streams with partially enabled
inter-layer prediction.

This change won't affect conventional SVC (inter-layer prediction is
enabled for all frames) since spatial index was always zero in this
case.

Bug: webrtc:9249
Change-Id: If6ff26a18b7cf543ec9e7f70b9239e9edff250b5
Reviewed-on: https://webrtc-review.googlesource.com/74924
Commit-Queue: Sergey Silkin <fc631354f276613a5410ea259cf4618b2846d39b@webrtc.org>
Reviewed-by: Philip Eliasson <729b5e2dca9359bca8c81d600ef9d3e554586ac9@webrtc.org>
Reviewed-by: Stefan Holmer <eb0877843acc39f8ef6f7269937dee931c372d23@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#23177}
TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc