Wait for crosvm in a separate thread, and keep track of when it dies.

This lets us tell whether a VM is still running or has finished. Also
add callback so clients can get notified when crosvm dies.

Bug: 171277638
Test: Ran on VIM3L
Test: atest VirtualizationTestCases
Change-Id: I52c1625af45cfcfe7aa0be465ea08f427ec5bc43
7 files changed
tree: 2b89c761bde49078b9898d88ba0bcc28c7ef3cfd
  1. apex/
  2. authfs/
  3. docs/
  4. microdroid/
  5. tests/
  6. virtmanager/
  7. vm/
  8. .clang-format
  9. PREUPLOAD.cfg