Revert of Split iOS sdk in to separate targets

webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnection+DataChannel.mm

-/*
- *  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 "RTCPeerConnection+Private.h"
-
-#import "NSString+StdString.h"
-#import "RTCDataChannel+Private.h"
-#import "RTCDataChannelConfiguration+Private.h"
-
-@implementation RTCPeerConnection (DataChannel)
-
-- (RTCDataChannel *)dataChannelForLabel:(NSString *)label
-                          configuration:
-    (RTCDataChannelConfiguration *)configuration {
-  std::string labelString = [NSString stdStringForString:label];
-  const webrtc::DataChannelInit nativeInit =
-      configuration.nativeDataChannelInit;
-  rtc::scoped_refptr<webrtc::DataChannelInterface> dataChannel =
-      self.nativePeerConnection->CreateDataChannel(labelString,
-                                                   &nativeInit);
-  if (!dataChannel) {
-    return nil;
-  }
-  return [[RTCDataChannel alloc] initWithNativeDataChannel:dataChannel];
-}
-
-@end