Make a friendlier RTCVideoCodecInfo initializer.

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

Index: webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCVideoCodec.mm
diff --git a/webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCVideoCodec.mm b/webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCVideoCodec.mm
index 1be33f0a8ff98a35e1c7a25203a3eab41a6ce460..4936568dd1b6fd04c5b4e96787b0c46508428127 100644
--- a/webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCVideoCodec.mm
+++ b/webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCVideoCodec.mm
@@ -20,13 +20,12 @@
 @synthesize name = _name;
 @synthesize parameters = _parameters;
 
-- (instancetype)initWithPayload:(NSInteger)payload
-                           name:(NSString *)name
-                     parameters:(NSDictionary<NSString *, NSString *> *)parameters {
+- (instancetype)initWithName:(NSString *)name
+                  parameters:(nullable NSDictionary<NSString *, NSString *> *)parameters {
   if (self = [super init]) {
-    _payload = payload;
+    _payload = 0;
     _name = name;
-    _parameters = parameters;
+    _parameters = (parameters ? parameters : @{});
   }
 
   return self;
@@ -43,6 +42,16 @@
                     parameters:params];
 }
 
+- (instancetype)initWithPayload:(NSInteger)payload
+                           name:(NSString *)name
+                     parameters:(NSDictionary<NSString *, NSString *> *)parameters {
+  if (self = [self initWithName:name parameters:parameters]) {
+    _payload = payload;
+  }
+
+  return self;
+}
+
 - (cricket::VideoCodec)nativeVideoCodec {
   cricket::VideoCodec codec([NSString stdStringForString:_name]);
   for (NSString *paramKey in _parameters.allKeys) {