Make RTCCameraPreviewView video rotation optional.

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

Index: webrtc/sdk/objc/Framework/Classes/RTCCameraPreviewView.m
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCCameraPreviewView.m b/webrtc/sdk/objc/Framework/Classes/RTCCameraPreviewView.m
index 5a60ba3e896ddd0585ab7746c261537faa46a9c6..6ea0e2a727b96c9208e7b7298d52e9adb8cca586 100644
--- a/webrtc/sdk/objc/Framework/Classes/RTCCameraPreviewView.m
+++ b/webrtc/sdk/objc/Framework/Classes/RTCCameraPreviewView.m
@@ -18,11 +18,20 @@
 @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;
@@ -39,7 +48,9 @@
   [super layoutSubviews];
 
   // Update the video orientation based on the device orientation.
-  [self setCorrectVideoOrientation];
+  if (_shouldUpdateVideoOrientationOnDeviceRotation) {
+    [self setCorrectVideoOrientation];
+  }
 }
 
 - (void)setCorrectVideoOrientation {