Add support for checking SnapshotStartingWindow in isAppWindowVisible assertions

This is required because sometimes an app acn be restarted in the background and when we reopen it the window doesn't show but instead the SnapshotStartingWindow shows until the window is ready. That extension of the API allows us to limit flakiness of tests by checking for SnapshotStartingWindow as a fallback

Test: atest FlickerLibTest:WindowManagerTraceSubjectTest#testCanDetectSnapshotStartingWindow

Bug: 208628307
Change-Id: I163a8a1e2444fcf09c72f9633d5d7687ddce9f60
4 files changed
tree: 74241991de48bacd3b5e7787922408a8354f17f4
  1. build/
  2. docs/
  3. emu_test/
  4. libraries/
  5. scripts/
  6. tests/
  7. utils/
  8. PREUPLOAD.cfg