Adding AecDump functionality to AppRTCDemo for iOS

BUG=webrtc:6229

Review-Url: https://codereview.webrtc.org/2253013006
Cr-Commit-Position: refs/heads/master@{#13927}
diff --git a/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h b/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
index f2da413..cdcac96 100644
--- a/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
+++ b/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
@@ -43,6 +43,8 @@
 @property(nonatomic, strong) NSURL *webSocketRestURL;
 @property(nonatomic, readonly) BOOL isLoopback;
 @property(nonatomic, readonly) BOOL isAudioOnly;
+@property(nonatomic, readonly) BOOL shouldMakeAecDump;
+@property(nonatomic, assign) BOOL isAecDumpActive;
 
 @property(nonatomic, strong)
     RTCMediaConstraints *defaultPeerConnectionConstraints;