Make RTCCameraPreviewView video rotation optional.

webrtc/sdk/objc/Framework/Classes/RTCCameraPreviewView.m

 /*
  *  Copyright 2015 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.
  */
 
 #import "WebRTC/RTCCameraPreviewView.h"
 
 #import <AVFoundation/AVFoundation.h>
 #import <UIKit/UIKit.h>
 
 #import "RTCDispatcher+Private.h"
 
 @implementation RTCCameraPreviewView
 
 @synthesize captureSession = _captureSession;
+@synthesize shouldUpdateVideoOrientationOnDeviceRotation =
+    _shouldUpdateVideoOrientationOnDeviceRotation;
 
 + (Class)layerClass {
   return [AVCaptureVideoPreviewLayer class];
 }
 
+- (instancetype)init {
+  if (self = [super init]) {
+    _shouldUpdateVideoOrientationOnDeviceRotation = YES;
+  }
+  return self;
+}
+
 - (void)setCaptureSession:(AVCaptureSession *)captureSession {
   if (_captureSession == captureSession) {
     return;
   }
   _captureSession = captureSession;
   AVCaptureVideoPreviewLayer *previewLayer = [self previewLayer];
   [RTCDispatcher dispatchAsyncOnType:RTCDispatcherTypeCaptureSession
                                block:^{
     previewLayer.session = captureSession;
   }];
 }
 
 - (void)layoutSubviews {
   [super layoutSubviews];
 
   // Update the video orientation based on the device orientation.
-  [self setCorrectVideoOrientation];
+  if (_shouldUpdateVideoOrientationOnDeviceRotation) {
+    [self setCorrectVideoOrientation];
+  }
 }
 
 - (void)setCorrectVideoOrientation {
   // Get current device orientation.
   UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
   AVCaptureVideoPreviewLayer *previewLayer = [self previewLayer];
 
   // First check if we are allowed to set the video orientation.
   if (previewLayer.connection.isVideoOrientationSupported) {
     // Set the video orientation based on device orientation.
@@ skipping 13 matching lines @@
   }
 }
 
 #pragma mark - Private
 
 - (AVCaptureVideoPreviewLayer *)previewLayer {
   return (AVCaptureVideoPreviewLayer *)self.layer;
 }
 
 @end