Compile rtc_api_objc on Mac.

webrtc/api/objc/RTCIceCandidate.h

Index: webrtc/api/objc/RTCIceCandidate.h
diff --git a/webrtc/api/objc/RTCIceCandidate.h b/webrtc/api/objc/RTCIceCandidate.h
index 41ea69e9912a59e6417b9bde7c20cd3326066afa..5150a67574cc9a3ed878b55dfd5b3b6e5f5310c1 100644
--- a/webrtc/api/objc/RTCIceCandidate.h
+++ b/webrtc/api/objc/RTCIceCandidate.h
@@ -27,16 +27,16 @@ NS_ASSUME_NONNULL_BEGIN
 @property(nonatomic, readonly) NSInteger sdpMLineIndex;
 
 /** The SDP string for this candidate. */
-@property(nonatomic, readonly) NSString *sdp;
+@property(nonatomic, readonly, nonnull) NSString *sdp;
 
-- (instancetype)init NS_UNAVAILABLE;
+- (nonnull instancetype)init NS_UNAVAILABLE;

[tkchin_webrtc, 2016/02/24 22:39:18]

shouldn't init returns be nullable? It's possible that classes are unable to
init themselves and return nil.
Well actually if there were any return nils the compiler should be complaining
at you.
As long as init methods aren't returning nil because it failed to init itself,
nonnull attr should be fine, otherwise should be nullable

ditto for other classes in the CL

 
 /**
  * Initialize an RTCIceCandidate from SDP.
  */
-- (instancetype)initWithSdp:(NSString *)sdp
-              sdpMLineIndex:(NSInteger)sdpMLineIndex
-                     sdpMid:(nullable NSString *)sdpMid
+- (nonnull instancetype)initWithSdp:(nonnull NSString *)sdp
+                      sdpMLineIndex:(NSInteger)sdpMLineIndex
+                             sdpMid:(nullable NSString *)sdpMid
     NS_DESIGNATED_INITIALIZER;
 
 @end