Fixed booting logic on ActivityTaskSupervisor.activityIdleInternal()

It was clearing the list of users being switched when the device is
"booting", which could be a problem on systems running on headless
mode: if the method was called by a non-null record (like the
FallBackHome) before it was called by null, the non-system user would
never finish switching.

Test: manual verification # on automotive and phones

Fixes: 190854171
Bug: 203885241

Change-Id: I4c589fd618b104689434bf918ebb48a64cef30e4

services/core/java/com/android/server/am/ActivityManagerService.java

@@ -4932,6 +4932,8 @@ public class ActivityManagerService extends IActivityManager.Stub
 
     @Override
     public void bootAnimationComplete() {
+        if (DEBUG_ALL) Slog.d(TAG, "bootAnimationComplete: Callers=" + Debug.getCallers(4));
+
         final boolean callFinishBooting;
         synchronized (this) {
             callFinishBooting = mCallFinishBooting;
@@ -7765,7 +7767,7 @@ public class ActivityManagerService extends IActivityManager.Stub
 
         // On Automotive, at this point the system user has already been started and unlocked,
         // and some of the tasks we do here have already been done. So skip those in that case.
-        // TODO(b/132262830): this workdound shouldn't be necessary once we move the
+        // TODO(b/132262830, b/203885241): this workdound shouldn't be necessary once we move the
         // headless-user start logic to UserManager-land
         final boolean bootingSystemUser = currentUserId == UserHandle.USER_SYSTEM;
 

services/core/java/com/android/server/am/UserState.java

@@ -145,4 +145,11 @@ public final class UserState {
         proto.write(UserStateProto.SWITCHING, switching);
         proto.end(token);
     }
+
+    @Override
+    public String toString() {
+        return "[UserState: id=" + mHandle.getIdentifier() + ", state=" + stateToString(state)
+            + ", lastState=" + stateToString(lastState) + ", switching=" + switching
+            + ", tokenProvided=" + tokenProvided + "]";
+    }
 }

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

@@ -147,6 +147,7 @@ import com.android.internal.util.function.pooled.PooledLambda;
 import com.android.server.LocalServices;
 import com.android.server.am.ActivityManagerService;
 import com.android.server.am.UserState;
+import com.android.server.utils.Slogf;
 import com.android.server.wm.ActivityMetricsLogger.LaunchingState;
 
 import java.io.FileDescriptor;
@@ -1322,8 +1323,6 @@ public class ActivityTaskSupervisor implements RecentTasks.Callbacks {
             // us, we can now deliver.
             r.idle = true;
 
-            //Slog.i(TAG, "IDLE: mBooted=" + mBooted + ", fromTimeout=" + fromTimeout);
-
             // Check if able to finish booting when device is booting and all resumed activities
             // are idle.
             if ((mService.isBooting() && mRootWindowContainer.allResumedActivitiesIdle())
@@ -1356,14 +1355,21 @@ public class ActivityTaskSupervisor implements RecentTasks.Callbacks {
         // Atomically retrieve all of the other things to do.
         processStoppingAndFinishingActivities(r, processPausingActivities, "idle");
 
+        if (DEBUG_IDLE) {
+            Slogf.i(TAG, "activityIdleInternal(): r=%s, booting=%b, mStartingUsers=%s", r, booting,
+                    mStartingUsers);
+        }
+
         if (!mStartingUsers.isEmpty()) {
             final ArrayList<UserState> startingUsers = new ArrayList<>(mStartingUsers);
             mStartingUsers.clear();
-
-            if (!booting) {
+            // TODO(b/190854171): remove the isHeadlessSystemUserMode() check on master
+            if (!booting || UserManager.isHeadlessSystemUserMode()) {
                 // Complete user switch.
                 for (int i = 0; i < startingUsers.size(); i++) {
-                    mService.mAmInternal.finishUserSwitch(startingUsers.get(i));
+                    UserState userState = startingUsers.get(i);
+                    Slogf.i(TAG, "finishing switch of user %d", userState.mHandle.getIdentifier());
+                    mService.mAmInternal.finishUserSwitch(userState);
                 }
             }
         }
@@ -2012,6 +2018,7 @@ public class ActivityTaskSupervisor implements RecentTasks.Callbacks {
 
     final void scheduleIdle() {
         if (!mHandler.hasMessages(IDLE_NOW_MSG)) {
+            if (DEBUG_IDLE) Slog.d(TAG_IDLE, "scheduleIdle: Callers=" + Debug.getCallers(4));
             mHandler.sendEmptyMessage(IDLE_NOW_MSG);
         }
     }