Make a friendlier RTCVideoCodecInfo initializer.

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

 /*
  *  Copyright 2017 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.
  */
 
@@ skipping 14 matching lines @@
                      parameters:(NSDictionary<NSString *, NSString *> *)parameters {
   if (self = [super init]) {
     _payload = payload;
     _name = name;
     _parameters = parameters;
   }
 
   return self;
 }
 
+- (instancetype)initWithName:(NSString *)name
+                  parameters:(nullable NSDictionary<NSString *, NSString *> *)parameters {
+  return [self initWithPayload:0 name:name parameters:(parameters ? parameters : @{})];
+}
+
 - (instancetype)initWithNativeVideoCodec:(cricket::VideoCodec)videoCodec {
   NSMutableDictionary *params = [NSMutableDictionary dictionary];
   for (auto it = videoCodec.params.begin(); it != videoCodec.params.end(); ++it) {
     [params setObject:[NSString stringForStdString:it->second]
                forKey:[NSString stringForStdString:it->first]];
   }
   return [self initWithPayload:videoCodec.id
                           name:[NSString stringForStdString:videoCodec.name]
                     parameters:params];
 }
@@ skipping 17 matching lines @@
 
 - (instancetype)initWithThresholdsLow:(NSInteger)low high:(NSInteger)high {
   if (self = [super init]) {
     _low = low;
     _high = high;
   }
   return self;
 }
 
 @end