Revert "Injectable logging"

This reverts commit 59216ec4a4151b1ba5478c8f2b5c9f01f4683d7f.

Reason for revert:  forces all logs to have identical tag

Original change's description:
> Injectable logging
> 
> Allows passing a Loggable to PCFactory.initializationOptions, which
> is then injected to Logging.java and logging.h. Future log messages
> in both Java and native will then be passed to this Loggable.
> 
> Bug: webrtc:9225
> Change-Id: I2ff693380639448301a78a93dc11d3a0106f0967
> Reviewed-on: https://webrtc-review.googlesource.com/73243
> Commit-Queue: Paulina Hensman <phensman@webrtc.org>
> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#23241}

TBR=magjed@webrtc.org,sakal@webrtc.org,kwiberg@webrtc.org,phensman@webrtc.org

Change-Id: I27c9587238325b69b26166434740869021b7db8a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:9225
Reviewed-on: https://webrtc-review.googlesource.com/76885
Reviewed-by: Alex Glaznev <glaznev@webrtc.org>
Commit-Queue: Alex Glaznev <glaznev@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23253}

rtc_base/java/src/org/webrtc/Loggable.java

@@ -1,22 +0,0 @@
-/*
- *  Copyright (c) 2018 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.
- */
-
-package org.webrtc;
-
-import org.webrtc.Logging.Severity;
-
-/**
- * Java interface for WebRTC logging. The default implementation uses webrtc.Logging.
- *
- * When injected, the Loggable will receive logging from both Java and native.
- */
-public interface Loggable {
-  public void onLogMessage(String message, Severity severity, String tag);
-}