The SpatialIndex value from an EncodedImage is 0-based, but values were off by 1. Bug: none Change-Id: Ie74e6450ddef1cfaee68fa230c441030fa86a64a Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/203525 Reviewed-by: Erik Språng <sprang@webrtc.org> Commit-Queue: Florent Castelli <orphis@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33067}