commit 8bda21893e872cb1dc469d2980c7b40a6d512ebd
author Riddle Hsu <riddlehsu@google.com> Mon Mar 15 18:23:39 2021 +0800
committer Riddle Hsu <riddlehsu@google.com> Mon Mar 15 23:59:51 2021 +0800
tree 7bca67ee78d505bac0f14619cb9fbc10431adab9
parent a7ee1a9a4936985dc0e672903b1a3c45e68d1ef8

Activity in foreground task should be able to launch activity

Assume a visible task contains 2 activities:
 Activity B, process X (top-visible)
 Activity A, process Y
Though process Y doesn't have visible activity, it shouldn't be
blocked to launch activity because it is in a visible task.

This restores the accidental behavior change in commit 9b7603b.

Also simplify rankTaskLayers to reduce unnecessary anonymous class
and duplicated states (changed/scheduled).

Bug: 182694325
Test: atest RootWindowContainerTests#testTaskLayerRank
            BackgroundActivityLaunchTest# \
            testActivityNotBlockedFromBgActivityInFgTask
Change-Id: Ia8739967805aa8a43f99ab18840b02ac50380912