Make a friendlier RTCVideoCodecInfo initializer for when only name and

parameters are interesting.

Since this is used by users when implementing injectable Obj-C video
codecs, the API where the unused payload is required is unnecessarily
confusing. Also make the codec parameters optional.

BUG=None

Review-Url: https://codereview.webrtc.org/3001183002
Cr-Commit-Position: refs/heads/master@{#19411}

webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCVideoCodec+Private.h

@@ -49,6 +49,9 @@ NS_ASSUME_NONNULL_BEGIN
 @interface RTCVideoCodecInfo ()
 
 - (instancetype)initWithNativeVideoCodec:(cricket::VideoCodec)videoCodec;
+- (instancetype)initWithPayload:(NSInteger)payload
+                           name:(NSString *)name
+                     parameters:(NSDictionary<NSString *, NSString *> *)parameters;
 - (cricket::VideoCodec)nativeVideoCodec;
 
 @end

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) {

webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCVideoCodecH264.mm

@@ -58,9 +58,7 @@ bool IsHighProfileEnabled() {
       @"packetization-mode" : @"1",
     };
     RTCVideoCodecInfo *constrainedHighInfo =
-        [[RTCVideoCodecInfo alloc] initWithPayload:0
-                                              name:codecName
-                                        parameters:constrainedHighParams];
+        [[RTCVideoCodecInfo alloc] initWithName:codecName parameters:constrainedHighParams];
     [codecs addObject:constrainedHighInfo];
   }
 
@@ -70,9 +68,7 @@ bool IsHighProfileEnabled() {
     @"packetization-mode" : @"1",
   };
   RTCVideoCodecInfo *constrainedBaselineInfo =
-      [[RTCVideoCodecInfo alloc] initWithPayload:0
-                                            name:codecName
-                                      parameters:constrainedBaselineParams];
+      [[RTCVideoCodecInfo alloc] initWithName:codecName parameters:constrainedBaselineParams];
   [codecs addObject:constrainedBaselineInfo];
 
   return [codecs copy];
@@ -93,7 +89,7 @@ bool IsHighProfileEnabled() {
 
 - (NSArray<RTCVideoCodecInfo *> *)supportedCodecs {
   NSString *codecName = [NSString stringWithUTF8String:cricket::kH264CodecName];
-  return @[ [[RTCVideoCodecInfo alloc] initWithPayload:0 name:codecName parameters:@{}] ];
+  return @[ [[RTCVideoCodecInfo alloc] initWithName:codecName parameters:nil] ];
 }
 
 @end