ActivityTaskManagerService: clear previous if it becomes topApp

The same app shouldn't be top and previous. When topApp changes, if
the same app is previous, clear previous.

Test: atest WmTests:WindowStateTests
Bug: 262213347

Change-Id: Ia0e3fd2adf1c9c16e8d24b89785d6cd33f74d962

parent 8e2fe256

services/core/java/com/android/server/wm/ActivityTaskManagerService.java

+1 −0

Original line number	Diff line number	Diff line
		@@ -4841,6 +4841,7 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
		// If there is no resumed activity, it will choose the pausing or focused activity.
		: mRootWindowContainer.getTopResumedActivity();
		mTopApp = top != null ? top.app : null;
		if (mTopApp == mPreviousProcess) mPreviousProcess = null;
		}

		/**