Fix issues with TRON app transition logging

There was a case where a app launch started activity A. A step in
the UI finished A and started B in the same task. Next time A was
started it immediately finished itself, putting B at the top of
the task. Now, this launch was considered aborted because A was
finished during launching, making it invisible.

We fix this by modifying the logic to only abort the launch if the
full task is not visible anymore after an activity has been set to
invisible.

There is another case where an app launches A, finishes A, and then
launches B. In this case the home gets visible in between so we
don't consider this an app launch anymore, and correctly cancel
the logging. However it's still useful to know that this is
happening to expose it to the developer, so we log any cancel
events, no matter where they are coming from.

Test: Launch Snapchat, click Sign Up, click home, relaunch
Snapchat from home
Test: Open slow app and press home quickly to test cancel.

Change-Id: I211636c97fd6785adb3fe443a8ffa1ae766946a4
Merged-In: I211636c97fd6785adb3fe443a8ffa1ae766946a4
Fixes: 67094673