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 <Foundation/Foundation.h>
+#import <AVFoundation/AVFoundation.h>
+
+#include "avfoundationvideocapturer.h"
+
+NS_ASSUME_NONNULL_BEGIN
+// This class used to capture frames using AVFoundation APIs on iOS. It is meant
+// to be owned by an instance of AVFoundationVideoCapturer. The reason for this
+// 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

[kthelgason, 2016/11/10 09:28:10]

Don't we prefer classname+private.h over classnameInternal? Or are these
different concepts?

[daniela-webrtc, 2016/11/11 13:08:58]

I think they are different concepts. Class+Private.h is used for adding
extension to certain class (slightly different concept than extension).
From Apple docs:
"Class extensions are often used to extend the public interface with additional
private methods or properties for use within the implementation of the class
itself."
The most common case of class extension in the form of Class+Private I've seen
are for testing purposes.
This class however I believe it was suffixed Internal, to indicate that it's not
part of the public headers and that it's meant for internal use within the
framework only. 

+    : 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