Add new view that renders local video using AVCaptureLayerPreview.

talk/app/webrtc/objc/public/RTCCameraPreviewView.h

Index: talk/app/webrtc/objc/public/RTCCameraPreviewView.h
diff --git a/webrtc/examples/objc/AppRTCDemo/ios/UIImage+ARDUtilities.h b/talk/app/webrtc/objc/public/RTCCameraPreviewView.h
similarity index 55%
copy from webrtc/examples/objc/AppRTCDemo/ios/UIImage+ARDUtilities.h
copy to talk/app/webrtc/objc/public/RTCCameraPreviewView.h
index d56ba02c2eff4475d9a530cf3c3007c6828ffb2a..49cc567141849eefc6310c307ffc298a972972fa 100644
--- a/webrtc/examples/objc/AppRTCDemo/ios/UIImage+ARDUtilities.h
+++ b/talk/app/webrtc/objc/public/RTCCameraPreviewView.h
@@ -8,11 +8,18 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#import <Foundation/Foundation.h>
 #import <UIKit/UIKit.h>
 
-@interface UIImage (ARDUtilities)
+@class AVCaptureSession;
+@class RTCAVFoundationVideoSource;
 
-// Returns an color tinted version for the given image resource.
-+ (UIImage *)imageForName:(NSString *)name color:(UIColor *)color;
+/** RTCCameraPreviewView is a view that renders local video from an
+ *  AVCaptureSession 
+ */
+@interface RTCCameraPreviewView : UIView
+
+/** The video source being rendered in the view. */
+@property(nonatomic, strong) RTCAVFoundationVideoSource *videoSource;
 
 @end