Injectable software codecs for Android.

This is similar to https://webrtc-review.googlesource.com/c/src/+/3620
for iOS.

Using the new WebRtcMediaEngineFactory::Create API, the built-in
software video codecs are no longer appended to the injected codecs.

To be able to use the software codecs, they are exposed as Java
classes through SoftwareVideoEncoderFactory etc.

There is also a new DefaultVideoEncoderFactory used by AppRTCMobile.
This factory tries to use hardware implementations where available,
but falls back to using the injected software codecs.

The HardwareVideoEncoderFactory is temporarily also falling back on
the software codecs in its default configuration in order to
maintain backwards compatibility.

Bug: webrtc:7925
Change-Id: I3e8c5ed492ccd160aca968986ad217d7978a951c
Reviewed-on: https://webrtc-review.googlesource.com/17480
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Anders Carlsson <andersc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20647}

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

@@ -0,0 +1,70 @@
+/*
+ *  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;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class DefaultVideoEncoderFactory implements VideoEncoderFactory {
+  private final VideoEncoderFactory hardwareVideoEncoderFactory;
+  private final VideoEncoderFactory softwareVideoEncoderFactory;
+
+  public DefaultVideoEncoderFactory(
+      EglBase.Context eglContext, boolean enableIntelVp8Encoder, boolean enableH264HighProfile) {
+    hardwareVideoEncoderFactory = new HardwareVideoEncoderFactory(
+        eglContext, enableIntelVp8Encoder, enableH264HighProfile, false /* fallbackToSoftware */);
+    softwareVideoEncoderFactory = new SoftwareVideoEncoderFactory();
+  }
+
+  /* This is used for testing. */
+  DefaultVideoEncoderFactory(VideoEncoderFactory hardwareVideoEncoderFactory) {
+    this.hardwareVideoEncoderFactory = hardwareVideoEncoderFactory;
+    softwareVideoEncoderFactory = new SoftwareVideoEncoderFactory();
+  }
+
+  @Override
+  public VideoEncoder createEncoder(VideoCodecInfo info) {
+    List<VideoCodecInfo> hardwareSupportedCodecs =
+        Arrays.asList(hardwareVideoEncoderFactory.getSupportedCodecs());
+    if (containsSameCodec(hardwareSupportedCodecs, info)) {
+      return hardwareVideoEncoderFactory.createEncoder(info);
+    } else {
+      return softwareVideoEncoderFactory.createEncoder(info);
+    }
+  }
+
+  @Override
+  public VideoCodecInfo[] getSupportedCodecs() {
+    List<VideoCodecInfo> supportedCodecInfos = new ArrayList<>();
+
+    supportedCodecInfos.addAll(Arrays.asList(softwareVideoEncoderFactory.getSupportedCodecs()));
+
+    for (VideoCodecInfo info : hardwareVideoEncoderFactory.getSupportedCodecs()) {
+      if (!containsSameCodec(supportedCodecInfos, info)) {
+        supportedCodecInfos.add(info);
+      }
+    }
+
+    return supportedCodecInfos.toArray(new VideoCodecInfo[supportedCodecInfos.size()]);
+  }
+
+  private static boolean containsSameCodec(List<VideoCodecInfo> infos, VideoCodecInfo info) {
+    for (VideoCodecInfo otherInfo : infos) {
+      if (isSameCodec(info, otherInfo)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  private static native boolean isSameCodec(VideoCodecInfo info1, VideoCodecInfo info2);
+}