Add Java support for AudioProcessing and PostProcessing injection

This allows injection of a user-defined post processing module from
the Android layer.

Bug: webrtc:8163
Change-Id: If3a6b4726c34c5f82d186b8cf95373c283cbd3f6
Reviewed-on: https://webrtc-review.googlesource.com/7610
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Commit-Queue: Sam Zackrisson <saza@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20367}

sdk/android/api/org/webrtc/DefaultAudioProcessingFactory.java

@@ -0,0 +1,47 @@
+/*
+ *  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.
+ */
+
+package org.webrtc;
+
+/** Factory for instantiating the default webrtc::AudioProcessing implementation. */
+public class DefaultAudioProcessingFactory implements AudioProcessingFactory {
+  public DefaultAudioProcessingFactory() {
+    this(null /* postProcessingFactory */);
+  }
+
+  /**
+   * Allows injecting a PostProcessingFactory. A null PostProcessingFactory creates a
+   * webrtc::AudioProcessing with nullptr webrtc::postProcessing.
+   */
+  public DefaultAudioProcessingFactory(PostProcessingFactory postProcessingFactory) {
+    this.postProcessingFactory = postProcessingFactory;
+  }
+
+  /**
+   * Creates a default webrtc::AudioProcessing module, which takes ownership of objects created by
+   * its factories.
+   */
+  @Override
+  public long createNative() {
+    long nativePostProcessor = 0;
+    if (postProcessingFactory != null) {
+      nativePostProcessor = postProcessingFactory.createNative();
+      if (nativePostProcessor == 0) {
+        throw new NullPointerException(
+            "PostProcessingFactory.createNative() may not return 0 (nullptr).");
+      }
+    }
+    return nativeCreateAudioProcessing(nativePostProcessor);
+  }
+
+  private PostProcessingFactory postProcessingFactory;
+
+  private static native long nativeCreateAudioProcessing(long nativePostProcessor);
+}