Remove rtc_base/Dummy.java.

This has been introduced during the base -> rtc_base migration [1]
but it is no longer needed.

[1] - https://chromium-review.googlesource.com/c/external/webrtc/+/541215

Bug: webrtc:9838
Change-Id: Ibe3c58362e450682cefaa1ccda1b6d4eff606f45
No-Try: True
Reviewed-on: https://webrtc-review.googlesource.com/c/105664
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25156}
diff --git a/rtc_base/Dummy.java b/rtc_base/Dummy.java
deleted file mode 100644
index d8f02c9..0000000
--- a/rtc_base/Dummy.java
+++ /dev/null
@@ -1,19 +0,0 @@
-/*
- *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-/**
- * This class only exists as glue in a transition.
- * TODO(kjellander): Remove.
- * See https://bugs.webrtc.org/7634 for more details.
- */
-class Dummy {
-  Dummy() {
-  }
-}