[Chromecast] Fix bad channel selection for mono inputs

Bug: internal b/144923441
Change-Id: I0700c880c7600c31de8e5515df5ff1f900ea3568
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1931755
Reviewed-by: Le-Chun Wu <lcwu@chromium.org>
Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Commit-Queue: Kenneth MacKay <kmackay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718483}
1 file changed