Remove some unused classes.

Resolves signalapp/Signal-Android#14636

app/src/main/java/org/thoughtcrime/securesms/jobmanager/DependencyInjector.java

@@ -1,24 +0,0 @@
-/**
- * Copyright (C) 2014 Open Whisper Systems
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package org.thoughtcrime.securesms.jobmanager;
-
-/**
- * Interface responsible for injecting dependencies into Jobs.
- */
-public interface DependencyInjector {
-  void injectDependencies(Object object);
-}