Add Android native API: CreateJavaVideoSource

Adds Android native API for creating VideoTrackSourceInterface objects
that can be fed frames using VideoCapturer.CapturerObserver.

NativeCapturerObserver is moved out of VideoSource because it will now
be used without a VideoSource. It now takes a pointer to
AndroidVideoTrackSource directly instead of VideoTrackSourceProxy.

VideoSource and NativeCapturerObserver JNI code is moved away from
androidvideotracksource.cc to their own files. This allows using
AndroidVideoTrackSource independently.

Bug: webrtc:8769
Change-Id: Ifb9e1eb27d4c8237597d19d932ca6e863abb4d27
Reviewed-on: https://webrtc-review.googlesource.com/76924
Reviewed-by: Paulina Hensman <phensman@webrtc.org>
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23269}

sdk/android/src/java/org/webrtc/NativeCapturerObserver.java

@@ -0,0 +1,90 @@
+/*
+ *  Copyright (c) 2013 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 javax.annotation.Nullable;
+
+/**
+ * Implements VideoCapturer.CapturerObserver and feeds frames to
+ * webrtc::jni::AndroidVideoTrackSource.
+ */
+@JNINamespace("webrtc::jni")
+class NativeCapturerObserver implements VideoCapturer.CapturerObserver {
+  // Pointer to webrtc::jni::AndroidVideoTrackSource.
+  private final long nativeSource;
+  // TODO(bugs.webrtc.org/9181): Remove.
+  @Nullable private final SurfaceTextureHelper surfaceTextureHelper;
+
+  @CalledByNative
+  public NativeCapturerObserver(long nativeSource) {
+    this.nativeSource = nativeSource;
+    this.surfaceTextureHelper = null;
+  }
+
+  // TODO(bugs.webrtc.org/9181): Remove.
+  public NativeCapturerObserver(long nativeSource, SurfaceTextureHelper surfaceTextureHelper) {
+    this.nativeSource = nativeSource;
+    this.surfaceTextureHelper = surfaceTextureHelper;
+  }
+
+  @Override
+  public void onCapturerStarted(boolean success) {
+    nativeCapturerStarted(nativeSource, success);
+  }
+
+  @Override
+  public void onCapturerStopped() {
+    nativeCapturerStopped(nativeSource);
+  }
+
+  // TODO(bugs.webrtc.org/9181): Remove.
+  @Override
+  @SuppressWarnings("deprecation")
+  public void onByteBufferFrameCaptured(
+      byte[] data, int width, int height, int rotation, long timestampNs) {
+    // This NV21Buffer is not possible to retain. This is safe only because the native code will
+    // always call cropAndScale() and directly make a deep copy of the buffer.
+    final VideoFrame.Buffer nv21Buffer =
+        new NV21Buffer(data, width, height, null /* releaseCallback */);
+    final VideoFrame frame = new VideoFrame(nv21Buffer, rotation, timestampNs);
+    onFrameCaptured(frame);
+    frame.release();
+  }
+
+  // TODO(bugs.webrtc.org/9181): Remove.
+  @Override
+  @SuppressWarnings("deprecation")
+  public void onTextureFrameCaptured(int width, int height, int oesTextureId,
+      float[] transformMatrix, int rotation, long timestampNs) {
+    final VideoFrame.Buffer buffer = surfaceTextureHelper.createTextureBuffer(
+        width, height, RendererCommon.convertMatrixToAndroidGraphicsMatrix(transformMatrix));
+    final VideoFrame frame = new VideoFrame(buffer, rotation, timestampNs);
+    onFrameCaptured(frame);
+    frame.release();
+  }
+
+  @Override
+  public void onFrameCaptured(VideoFrame frame) {
+    nativeOnFrameCaptured(nativeSource, frame.getBuffer().getWidth(), frame.getBuffer().getHeight(),
+        frame.getRotation(), frame.getTimestampNs(), frame.getBuffer());
+  }
+
+  public void dispose() {
+    if (surfaceTextureHelper != null) {
+      surfaceTextureHelper.dispose();
+    }
+  }
+
+  private static native void nativeCapturerStarted(long source, boolean success);
+  private static native void nativeCapturerStopped(long source);
+  private static native void nativeOnFrameCaptured(
+      long source, int width, int height, int rotation, long timestampNs, VideoFrame.Buffer frame);
+}