Protect DownloadController instantiation

Enforce the use of DownloadService to create new DownloadController
instaces, but give access to the existing instances to anyone.

src/org/lineageos/updater/UpdatesActivity.java

@@ -31,6 +31,9 @@ import android.support.v7.widget.SimpleItemAnimator;
 import android.util.Log;
 
 import org.json.JSONException;
+import org.lineageos.updater.controller.DownloadController;
+import org.lineageos.updater.controller.DownloadControllerInt;
+import org.lineageos.updater.controller.DownloadService;
 import org.lineageos.updater.misc.Utils;
 
 import java.io.File;

src/org/lineageos/updater/UpdatesListAdapter.java

@@ -25,6 +25,7 @@ import android.widget.Button;
 import android.widget.ProgressBar;
 import android.widget.TextView;
 
+import org.lineageos.updater.controller.DownloadControllerInt;
 import org.lineageos.updater.misc.Utils;
 
 import java.io.IOException;

src/org/lineageos/updater/controller/DownloadController.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.lineageos.updater;
+package org.lineageos.updater.controller;
 
 import android.content.Context;
 import android.content.Intent;
@@ -23,6 +23,10 @@ import android.os.SystemClock;
 import android.support.v4.content.LocalBroadcastManager;
 import android.util.Log;
 
+import org.lineageos.updater.DownloadClient;
+import org.lineageos.updater.UpdateDownload;
+import org.lineageos.updater.UpdateStatus;
+import org.lineageos.updater.UpdatesDbHelper;
 import org.lineageos.updater.misc.Utils;
 
 import java.io.File;
@@ -55,7 +59,7 @@ public class DownloadController implements DownloadControllerInt {
         return sDownloadController;
     }
 
-    public static synchronized DownloadController getInstance(Context context) {
+    protected static synchronized DownloadController getInstance(Context context) {
         if (sDownloadController == null) {
             sDownloadController = new DownloadController(context);
         }

src/org/lineageos/updater/controller/DownloadControllerInt.java

@@ -13,7 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.lineageos.updater;
+package org.lineageos.updater.controller;
+
+import org.lineageos.updater.UpdateDownload;
 
 import java.util.List;
 import java.util.Set;

src/org/lineageos/updater/controller/DownloadService.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.lineageos.updater;
+package org.lineageos.updater.controller;
 
 import android.app.NotificationManager;
 import android.app.PendingIntent;
@@ -30,6 +30,9 @@ import android.text.format.DateUtils;
 import android.text.format.Formatter;
 import android.util.Log;
 
+import org.lineageos.updater.R;
+import org.lineageos.updater.UpdateDownload;
+import org.lineageos.updater.UpdatesActivity;
 import org.lineageos.updater.misc.Utils;
 
 import java.io.IOException;