Ping backup connection at a slower rate

talk/app/webrtc/objc/public/RTCPeerConnectionInterface.h

Index: talk/app/webrtc/objc/public/RTCPeerConnectionInterface.h
diff --git a/talk/app/webrtc/objc/public/RTCPeerConnectionInterface.h b/talk/app/webrtc/objc/public/RTCPeerConnectionInterface.h
index b0cc72b5b7982457d0a54042ff190cf950dafb3a..44b971c85e5e725ec2ea3abdb97b0c9bdbc95946 100644
--- a/talk/app/webrtc/objc/public/RTCPeerConnectionInterface.h
+++ b/talk/app/webrtc/objc/public/RTCPeerConnectionInterface.h
@@ -64,12 +64,14 @@ typedef NS_ENUM(NSInteger, RTCTcpCandidatePolicy) {
 @property(nonatomic, assign) RTCTcpCandidatePolicy tcpCandidatePolicy;
 @property(nonatomic, assign) int audioJitterBufferMaxPackets;
 @property(nonatomic, assign) int iceConnectionReceivingTimeout;
+@property(nonatomic, assign) int iceBackupCandidatePairPingInterval;
 
 - (instancetype)initWithIceTransportsType:(RTCIceTransportsType)iceTransportsType
                              bundlePolicy:(RTCBundlePolicy)bundlePolicy
                             rtcpMuxPolicy:(RTCRtcpMuxPolicy)rtcpMuxPolicy
                        tcpCandidatePolicy:(RTCTcpCandidatePolicy)tcpCandidatePolicy
               audioJitterBufferMaxPackets:(int)audioJitterBufferMaxPackets
-            iceConnectionReceivingTimeout:(int)iceConnectionReceivingTimeout;
+            iceConnectionReceivingTimeout:(int)iceConnectionReceivingTimeout
+       iceBackupCandidatePairPingInterval:(int)iceBackupCandidatePairPingInterval;
 
 @end