Update API for Objective-C RTCMediaStreamTrack

webrtc/api/objc/RTCMediaStreamTrack+Private.h

+/*
+ *  Copyright 2015 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 "RTCMediaStreamTrack.h"
+
+#include "talk/app/webrtc/mediastreaminterface.h"
+#include "webrtc/base/scoped_ptr.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RTCMediaStreamTrack ()
+
+/**
+ * The native MediaStreamTrackInterface representation of this
+ * RTCMediaStreamTrack object. This is needed to pass to the underlying C++
+ * APIs.
+ */
+@property(nonatomic, readonly)
+    rtc::scoped_refptr<webrtc::MediaStreamTrackInterface> nativeTrack;
+
+/**
+ * Initialize an RTCMediaStreamTrack from a native MediaStreamTrackInterface.
+ */
+- (instancetype)initWithNativeTrack:
+    (rtc::scoped_refptr<webrtc::MediaStreamTrackInterface>)nativeTrack
+    NS_DESIGNATED_INITIALIZER;
+
++ (webrtc::MediaStreamTrackInterface::TrackState)nativeTrackStateForState:
+    (RTCMediaStreamTrackState)state;
+
++ (RTCMediaStreamTrackState)trackStateForNativeState:
+    (webrtc::MediaStreamTrackInterface::TrackState)nativeState;
+
++ (NSString *)stringForState:(RTCMediaStreamTrackState)state;
+
+@end
+
+NS_ASSUME_NONNULL_END