Show toast for transcoding denials

We may show toasts in these 3 cases:
1. Transcoding request was just dropped for uid
2. Transcoding request has been dropped for uid during current boot
3. File is longer than max allowed transcoding duration

Even after any of the conditions above have been met, if the app is
not foreground or we have already shown a toast while the app
is still foreground, we do not show any new toasts

Bug: 170973510
Test: Manual

Change-Id: I6540bf9201ca14aecb5dbde64b6991334d3d3bca
2 files changed