Reland of Support adding and removing MediaRecorder to camera 2 session. (patchset #1 id:1 of https://codereview.webrtc.org/2844233002/ )

Reason for revert:
Revert "Revert of Support adding and removing MediaRecorder to camera 2 session. (patchset #5 id:80001 of https://codereview.webrtc.org/2833773003/ )"

Will fix external bots by cherry picking this CL and updating external functions which depend on CameraVideoCapturer interface

Original issue's description:
> Revert of Support adding and removing MediaRecorder to camera 2 session. (patchset #5 id:80001 of https://codereview.webrtc.org/2833773003/ )
>
> Reason for revert:
> Breaks external bot
>
> Original issue's description:
> > Support adding and removing MediaRecorder to camera 2 session.
> >
> > Camera 1 API is not supported.
> >
> > BUG=b/36684011
> >
> > Review-Url: https://codereview.webrtc.org/2833773003
> > Cr-Commit-Position: refs/heads/master@{#17901}
> > Committed: 2fc04769fa
>
> TBR=sakal@webrtc.org,glaznev@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=b/36684011
>
> Review-Url: https://codereview.webrtc.org/2844233002
> Cr-Commit-Position: refs/heads/master@{#17905}
> Committed: 6702739862

TBR=sakal@webrtc.org,magjed@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=b/36684011

Review-Url: https://codereview.webrtc.org/2844393002
Cr-Commit-Position: refs/heads/master@{#17915}

webrtc/sdk/android/api/org/webrtc/Camera1Capturer.java

@@ -10,11 +10,8 @@
 
 package org.webrtc;
 
-import org.webrtc.CameraEnumerationAndroid.CaptureFormat;
-
 import android.content.Context;
-
-import java.util.List;
+import android.media.MediaRecorder;
 
 public class Camera1Capturer extends CameraCapturer {
   private final boolean captureToTexture;
@@ -29,8 +26,11 @@ public class Camera1Capturer extends CameraCapturer {
   @Override
   protected void createCameraSession(CameraSession.CreateSessionCallback createSessionCallback,
       CameraSession.Events events, Context applicationContext,
-      SurfaceTextureHelper surfaceTextureHelper, String cameraName, int width, int height,
-      int framerate) {
+      SurfaceTextureHelper surfaceTextureHelper, MediaRecorder mediaRecorder, String cameraName,
+      int width, int height, int framerate) {
+    if (mediaRecorder != null) {
+      throw new RuntimeException("MediaRecoder is not supported for camera 1.");
+    }
     Camera1Session.create(createSessionCallback, events, captureToTexture, applicationContext,
         surfaceTextureHelper, Camera1Enumerator.getCameraIndex(cameraName), width, height,
         framerate);

webrtc/sdk/android/api/org/webrtc/Camera2Capturer.java

@@ -13,6 +13,7 @@ package org.webrtc;
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.hardware.camera2.CameraManager;
+import android.media.MediaRecorder;
 
 @TargetApi(21)
 public class Camera2Capturer extends CameraCapturer {
@@ -29,9 +30,9 @@ public class Camera2Capturer extends CameraCapturer {
   @Override
   protected void createCameraSession(CameraSession.CreateSessionCallback createSessionCallback,
       CameraSession.Events events, Context applicationContext,
-      SurfaceTextureHelper surfaceTextureHelper, String cameraName, int width, int height,
-      int framerate) {
+      SurfaceTextureHelper surfaceTextureHelper, MediaRecorder mediaRecoder, String cameraName,
+      int width, int height, int framerate) {
     Camera2Session.create(createSessionCallback, events, applicationContext, cameraManager,
-        surfaceTextureHelper, cameraName, width, height, framerate);
+        surfaceTextureHelper, mediaRecoder, cameraName, width, height, framerate);
   }
 }

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

@@ -10,6 +10,8 @@
 
 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
@@ -59,6 +61,32 @@ public interface CameraVideoCapturer extends VideoCapturer {
    */
   void switchCamera(CameraSwitchHandler switchEventsHandler);
 
+  /**
+   * MediaRecorder add/remove handler - one of these functions are invoked with the result of
+   * addMediaRecorderToCamera() or removeMediaRecorderFromCamera calls.
+   * 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.
+   * Once MediaRecorder is added to camera pipeline camera switch is not allowed.
+   * 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