Allow device owner app to start activities from background

Bug: 123689871
Bug: 110956953
Test: atest WmTests:ActivityStarterTests
Change-Id: I5d4a8e2e98d486187f65999fb7f7dd72d1413b70
diff --git a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
index 09ef4b9..14c4814 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
@@ -151,6 +151,7 @@
 import android.app.WaitResult;
 import android.app.WindowConfiguration;
 import android.app.admin.DevicePolicyCache;
+import android.app.admin.DevicePolicyManager;
 import android.app.assist.AssistContent;
 import android.app.assist.AssistStructure;
 import android.app.usage.UsageStatsManagerInternal;
@@ -362,6 +363,7 @@
     WindowManagerService mWindowManager;
     private UserManagerService mUserManager;
     private AppOpsService mAppOpsService;
+    private DevicePolicyManager mDpm;
     /** All active uids in the system. */
     private final SparseArray<Integer> mActiveUids = new SparseArray<>();
     private final SparseArray<String> mPendingTempWhitelist = new SparseArray<>();
@@ -836,6 +838,13 @@
         return mAppOpsService;
     }
 
+    DevicePolicyManager getDevicePolicyManager() {
+        if (mDpm == null) {
+            mDpm = mContext.getSystemService(DevicePolicyManager.class);
+        }
+        return mDpm;
+    }
+
     boolean hasUserRestriction(String restriction, int userId) {
         return getUserManager().hasUserRestriction(restriction, userId);
     }