Update blocking screen.

- Use opaque background to put blocked activity into Stopped state
- Add blocked app name and icon
- Add debug info for non-user build

Test: verified with demo app
Bug: 111264725
Fix: 116732464
Fix: 118714747
Change-Id: I7325d429d7e36a32f69f6331d5e8eea9633f3688
(cherry picked from commit 0c689e7192da62c5293f3b4aa9f55394b86be281)
15 files changed