Fixes crash when pinning unfocused task in multiwindow

If an app can invoke pin locked mode such as Play video, and is split to
the bottom/right and not focused (focus the primary split task), then it
will crash trying to start lock task mode. Fix by moving pinned task to
front to become focused.

Change-Id: Ifd2c91b90d0f9f29111321f6fb2a1c5cf0073c49
Fixes: 72868672
Test: manual

1 files changed, 5 insertions, 2 deletions

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 8d1632a3cef6..b666d1015c30 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -11283,8 +11283,11 @@ public class ActivityManagerService extends IActivityManager.Stub
         long ident = Binder.clearCallingIdentity();
         try {
             synchronized (this) {
-                startLockTaskModeLocked(mStackSupervisor.anyTaskForIdLocked(taskId),
-                        true /* isSystemCaller */);
+                final TaskRecord task = mStackSupervisor.anyTaskForIdLocked(taskId);
+
+                // When starting lock task mode the stack must be in front and focused
+                task.getStack().moveToFront("startSystemLockTaskMode");
+                startLockTaskModeLocked(task, true /* isSystemCaller */);
             }
         } finally {
             Binder.restoreCallingIdentity(ident);