Split iOS sdk in to separate targets

This CL splits the iOS sdk into separate static libraries for video,
audio, ui, common, and peerconnection-related code. This will in the
future make it easier to compile WebRTC without unneeded components.

BUG=webrtc:4867

Review-Url: https://codereview.webrtc.org/2862543002
Cr-Commit-Position: refs/heads/master@{#18166}

webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCRtpParameters.mm

@@ -0,0 +1,56 @@
+/*
+ *  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 "RTCRtpParameters+Private.h"
+
+#import "RTCRtpCodecParameters+Private.h"
+#import "RTCRtpEncodingParameters+Private.h"
+
+@implementation RTCRtpParameters
+
+@synthesize encodings = _encodings;
+@synthesize codecs = _codecs;
+
+- (instancetype)init {
+  return [super init];
+}
+
+- (instancetype)initWithNativeParameters:
+    (const webrtc::RtpParameters &)nativeParameters {
+  if (self = [self init]) {
+    NSMutableArray *encodings = [[NSMutableArray alloc] init];
+    for (const auto &encoding : nativeParameters.encodings) {
+      [encodings addObject:[[RTCRtpEncodingParameters alloc]
+                               initWithNativeParameters:encoding]];
+    }
+    _encodings = encodings;
+
+    NSMutableArray *codecs = [[NSMutableArray alloc] init];
+    for (const auto &codec : nativeParameters.codecs) {
+      [codecs addObject:[[RTCRtpCodecParameters alloc]
+                            initWithNativeParameters:codec]];
+    }
+    _codecs = codecs;
+  }
+  return self;
+}
+
+- (webrtc::RtpParameters)nativeParameters {
+    webrtc::RtpParameters parameters;
+  for (RTCRtpEncodingParameters *encoding in _encodings) {
+    parameters.encodings.push_back(encoding.nativeParameters);
+  }
+  for (RTCRtpCodecParameters *codec in _codecs) {
+    parameters.codecs.push_back(codec.nativeParameters);
+  }
+  return parameters;
+}
+
+@end