Support adding and removing MediaRecorder to camera 2 session.

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

 /*
  *  Copyright 2016 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 android.media.MediaRecorder;
+
 /**
  * Base interface for camera1 and camera2 implementations. Extends VideoCapturer with a
  * switchCamera() function. Also provides subinterfaces for handling camera events, and a helper
  * class for detecting camera freezes.
  */
 public interface CameraVideoCapturer extends VideoCapturer {
   /**
    * Camera events handler - can be used to be notifed about camera events. The callbacks are
    * executed from an arbitrary thread.
    */
@@ skipping 30 matching lines @@
     void onCameraSwitchError(String errorDescription);
   }
 
   /**
    * Switch camera to the next valid camera id. This can only be called while the camera is running.
    * This function can be called from any thread.
    */
   void switchCamera(CameraSwitchHandler switchEventsHandler);
 
   /**
+   * Media recorder handler - one of these functions are invoked with the result of switchCamera().

[magjed_webrtc, 2017/04/21 10:45:16]

nit: not switchCamera(), but
addMediaRecorderToCamera()/removeMediaRecorderFromCamera().

[AlexG, 2017/04/21 19:38:11]

Done.

+   * The callback may be called on an arbitrary thread.
+   */
+  public interface MediaRecorderHandler {
+    // Invoked on success.
+    void onMediaRecorderSuccess();
+
+    // Invoked on failure, e.g. camera is stopped or any exception happens.
+    void onMediaRecorderError(String errorDescription);
+  }
+
+  /**
+   * Add MediaRecorder to camera pipeline. This can only be called while the camera is running.
+   * This function can be called from any thread.
+   */
+  void addMediaRecorderToCamera(MediaRecorder mediaRecorder, MediaRecorderHandler resultHandler);
+
+  /**
+   * Remove MediaRecorder from camera pipeline. This can only be called while the camera is running.
+   * This function can be called from any thread.
+   */
+  void removeMediaRecorderFromCamera(MediaRecorderHandler resultHandler);
+
+  /**
    * Helper class to log framerate and detect if the camera freezes. It will run periodic callbacks
    * on the SurfaceTextureHelper thread passed in the ctor, and should only be operated from that
    * thread.
    */
   public static class CameraStatistics {
     private final static String TAG = "CameraStatistics";
     private final static int CAMERA_OBSERVER_PERIOD_MS = 2000;
     private final static int CAMERA_FREEZE_REPORT_TIMOUT_MS = 4000;
 
     private final SurfaceTextureHelper surfaceTextureHelper;
@@ skipping 48 matching lines @@
     public void addFrame() {
       checkThread();
       ++frameCount;
     }
 
     public void release() {
       surfaceTextureHelper.getHandler().removeCallbacks(cameraObserver);
     }
   }
 }