Split avfoundationcapturer classes in separate files.

webrtc/sdk/objc/Framework/Classes/RTCAVFoundationVideoCapturerInternal.h

+/*
+ *  Copyright 2016 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 <AVFoundation/AVFoundation.h>
+#import <Foundation/Foundation.h>
+
+#include "avfoundationvideocapturer.h"
+
+NS_ASSUME_NONNULL_BEGIN
+// This class is an implementation detail of AVFoundationVideoCapturer and handles
+// the ObjC integration with the AVFoundation APIs.
+// It is meant to be owned by an instance of AVFoundationVideoCapturer.
+// The reason for this is because other webrtc objects own cricket::VideoCapturer, which is not
+// ref counted. To prevent bad behavior we do not expose this class directly.
+
+@interface RTCAVFoundationVideoCapturerInternal
+    : NSObject<AVCaptureVideoDataOutputSampleBufferDelegate>
+
+@property(nonatomic, readonly) AVCaptureSession *captureSession;
+@property(nonatomic, readonly) dispatch_queue_t frameQueue;
+@property(nonatomic, readonly) BOOL canUseBackCamera;
+@property(nonatomic, assign) BOOL useBackCamera;  // Defaults to NO.
+@property(atomic, assign) BOOL isRunning;  // Whether the capture session is running.
+@property(atomic, assign) BOOL hasStarted;  // Whether we have an unmatched start.
+
+// We keep a pointer back to AVFoundationVideoCapturer to make callbacks on it
+// when we receive frames. This is safe because this object should be owned by
+// it.
+- (instancetype)initWithCapturer:(webrtc::AVFoundationVideoCapturer *)capturer;
+- (AVCaptureDevice *)getActiveCaptureDevice;
+
+- (nullable AVCaptureDevice *)frontCaptureDevice;
+- (nullable AVCaptureDevice *)backCaptureDevice;
+
+// Starts and stops the capture session asynchronously. We cannot do this
+// synchronously without blocking a WebRTC thread.
+- (void)start;
+- (void)stop;
+
+@end
+NS_ASSUME_NONNULL_END