Minor ObjC API tweaks.

webrtc/api/objc/RTCStatsReport.mm

Index: webrtc/api/objc/RTCStatsReport.mm
diff --git a/webrtc/api/objc/RTCStatsReport.mm b/webrtc/api/objc/RTCStatsReport.mm
index b3cd1a19efbf5355a1aa55b3791513092eb985e4..99cdd287b8a66a738b9ff36892ae54bbe2ae8675 100644
--- a/webrtc/api/objc/RTCStatsReport.mm
+++ b/webrtc/api/objc/RTCStatsReport.mm
@@ -20,12 +20,12 @@
 
 @synthesize timestamp = _timestamp;
 @synthesize type = _type;
-@synthesize statsId = _statsId;
+@synthesize reportId = _reportId;
 @synthesize values = _values;
 
 - (NSString *)description {
   return [NSString stringWithFormat:@"RTCStatsReport:\n%@\n%@\n%f\n%@",
-                                    _statsId,
+                                    _reportId,
                                     _type,
                                     _timestamp,
                                     _values];
@@ -37,7 +37,7 @@
   if (self = [super init]) {
     _timestamp = nativeReport.timestamp();
     _type = [NSString stringForStdString:nativeReport.TypeToString()];
-    _statsId = [NSString stringForStdString:
+    _reportId = [NSString stringForStdString:
         nativeReport.id()->ToString()];
 
     NSUInteger capacity = nativeReport.values().size();