Android VideoSource: Add adaptOutputFormat function

webrtc/api/android/java/src/org/webrtc/VideoSource.java

Index: webrtc/api/android/java/src/org/webrtc/VideoSource.java
diff --git a/webrtc/api/android/java/src/org/webrtc/VideoSource.java b/webrtc/api/android/java/src/org/webrtc/VideoSource.java
index f664f19d2c6842ffc313c729dab05b6d4dc8eda0..239940d765cc14b08d4e0a41c03bf7b8bd434315 100644
--- a/webrtc/api/android/java/src/org/webrtc/VideoSource.java
+++ b/webrtc/api/android/java/src/org/webrtc/VideoSource.java
@@ -12,14 +12,23 @@
 package org.webrtc;
 
 /**
- * Java version of VideoSourceInterface, extended with stop/restart
- * functionality to allow explicit control of the camera device on android,
- * where there is no support for multiple open capture devices and the cost of
- * holding a camera open (even if MediaStreamTrack.setEnabled(false) is muting
- * its output to the encoder) can be too high to bear.
+ * Java wrapper of native AndroidVideoTrackSource.
  */
 public class VideoSource extends MediaSource {
   public VideoSource(long nativeSource) {
     super(nativeSource);
   }
+
+  /**
+   * Calling this function will cause frames to be scaled down to the requested resolution. Also,
+   * frames will be cropped to match the requested aspect ratio, and frames will be dropped to match
+   * the requested fps. The requested aspect ratio is orientation agnostic and will be adjusted to
+   * maintain the input orientation, so it doesn't matter if e.g. 1280x720 or 720x1280 is requested.
+   */
+  public void adaptOutputFormat(int width, int height, int fps) {
+    nativeAdaptOutputFormat(nativeSource, width, height, fps);
+  }
+
+  private static native void nativeAdaptOutputFormat(
+      long nativeSource, int width, int height, int fps);
 }