Use unsigned long instead of long for positive values

webkit implementation already uses unsigned long for some of these https://github.com/WebKit/WebKit/blob/5858e9511bb3d3306db3c4bc0973c521cdc97a03/Source/WebCore/Modules/mediastream/RTCEncodedVideoFrame.idl

Author: dontcallmedom

index.bs

@@ -283,14 +283,14 @@ enum RTCEncodedVideoFrameType {
 };
 
 dictionary RTCEncodedVideoFrameMetadata {
-    long long frameId;
+    unsigned long long frameId;
     sequence<long long> dependencies;
     unsigned short width;
     unsigned short height;
-    long spatialIndex;
-    long temporalIndex;
-    long synchronizationSource;
-    sequence<long> contributingSources;
+    unsigned long spatialIndex;
+    unsigned long temporalIndex;
+    unsigned long synchronizationSource;
+    sequence<unsigned long> contributingSources;
 };
 
 // New interfaces to define encoded video and audio frames. Will eventually
@@ -304,8 +304,8 @@ interface RTCEncodedVideoFrame {
 };
 
 dictionary RTCEncodedAudioFrameMetadata {
-    long synchronizationSource;
-    sequence<long> contributingSources;
+    unsigned long synchronizationSource;
+    sequence<unsigned long> contributingSources;
 };
 
 [Exposed=(Window,DedicatedWorker)]