What happens if you do the same on a native application like Google Music or YouTube?

Does not repro for Google Music when playback is in foreground & background.
Also does not repro for YouTube in foreground.

I mean the bluetooth volume will be changed.

Would be nice to know what Android version it is for.

On Android N I see the volume buttons change the media volume (with an extra Bluetooth drawable next to the music note). If I expand the volume popup - it will show me a Chrome volume with the media router / cast icon that will be synced with the media volume - I can drag either of them and both will move to the same value.

I wonder if that't related to the issue but just works worse on older systems.

We do set the MediaSession on the MediaRouter object in MediaNotificationManager so the selected media route (bluetooth in this case) might affect how volume is changed.

If I cast something from Chrome, the volume popup shows the exact same extra "media route volume" slider as in the Bluetooth case but changing it doesn't change the local media volume.

Google Music, YouTube or Netflix don't cause an extra volume slider to show in the case of Bluetooth headphones but do show it when casting.

This is the line I'm talking about: https://cs.chromium.org/chromium/src/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java?rcl=1a07e633e4bcb14569d37908e64eae0198840007&l=986

Support7Demos seem to call setMediaSessionCompat on MediaRouter service unconditionally though :/

Support library also distinguishes the default and the bluetooth routes now.

Should this be marked as WontFix then?

Hm, how did you come to this conclusion?

1. I think we should exactly what Music and other apps do so the extra slider shouldn't show up in the case of a Bluetooth route -- it's likely we're doing something wrong.
2. The original issue sounds worse than what I experienced on my N phone -- maybe it's only reproducible on some other version of Android.

I tested on KK, L and O in addition to N. I haven't seen the original issue of changing between two volumes.

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Talked to zhiqiang@ the issue is not in flickering but that a different of the two synchronized sliders shows up depending on whether Chrome is in foreground (media volume) or background (media route volume) visually distinguished by the slider icon.

Do we still intend to fix this?