[iOS] Stop swizzling the |init| method of CameraController.

ios/chrome/browser/ui/qr_scanner/camera_controller.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef IOS_CHROME_BROWSER_UI_QR_SCANNER_CAMERA_CONTROLLER_H_
 #define IOS_CHROME_BROWSER_UI_QR_SCANNER_CAMERA_CONTROLLER_H_
 
 #import <AVFoundation/AVFoundation.h>
 #import <UIKit/UIKit.h>
 
@@ skipping 49 matching lines @@
 
 // The CameraController manages the AVCaptureSession, its inputs, outputs, and
 // notifications for the QRScannerViewController.
 @interface CameraController : NSObject
 
 // The current state of the torch.
 @property(nonatomic, readonly, assign, getter=isTorchActive) BOOL torchActive;
 
 - (instancetype)init NS_UNAVAILABLE;
 
-// Initializes the controller with the |delegate|.
-- (instancetype)initWithDelegate:(id<CameraControllerDelegate>)delegate
-    NS_DESIGNATED_INITIALIZER;
+// Returns a new controller with the |delegate|.
++ (instancetype)cameraControllerWithDelegate:
+    (id<CameraControllerDelegate>)delegate;
 
 // Returns the app's authorization in regards to the camera.
 - (AVAuthorizationStatus)getAuthorizationStatus;
 
 // Asks the user to grant the authorization to access the camera.
 // Should only be called when the current authorization status is
 // AVAuthorizationStatusNotDetermined.
 - (void)requestAuthorizationAndLoadCaptureSession:
     (AVCaptureVideoPreviewLayer*)previewLayer;
 
@@ skipping 18 matching lines @@
 // available.
 - (void)stopRecording;
 
 // Sets the camera's torch mode to |mode|. Does nothing if the camera is not
 // available or the torch mode is not supported.
 - (void)setTorchMode:(AVCaptureTorchMode)mode;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_QR_SCANNER_CAMERA_CONTROLLER_H_