UX Improvements to activity switcher
Provide better feedback after switching activities with Meta-Tab by showing the switcher for 1 second after the Meta key is released. This will help confused users who accidently switched activities. BUG: 349004
I also did some reorganizing inside SwitcherBackend and added comments.
Also, I'm unable to get "drop mode" to work on this MR or on master so I can't test that.