Objective-C API to set the ICE check rate through RTCConfiguration.

This is the Objective-C counterpart to
https://codereview.webrtc.org/2670053002/. Allows applications to
control the maximum ICE check rate to match bandwidth constraints.

BUG=webrtc:7082

Review-Url: https://codereview.webrtc.org/2674663002
Cr-Commit-Position: refs/heads/master@{#16423}

webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm

@@ -37,6 +37,7 @@
 @synthesize shouldPruneTurnPorts = _shouldPruneTurnPorts;
 @synthesize shouldPresumeWritableWhenFullyRelayed =
     _shouldPresumeWritableWhenFullyRelayed;
+@synthesize iceCheckMinInterval = _iceCheckMinInterval;
 
 - (instancetype)init {
   if (self = [super init]) {
@@ -68,13 +69,17 @@
     _shouldPruneTurnPorts = config.prune_turn_ports;
     _shouldPresumeWritableWhenFullyRelayed =
         config.presume_writable_when_fully_relayed;
+    if (config.ice_check_min_interval) {
+      _iceCheckMinInterval =
+          [NSNumber numberWithInt:*config.ice_check_min_interval];
+    }
   }
   return self;
 }
 
 - (NSString *)description {
   return [NSString stringWithFormat:
-      @"RTCConfiguration: {\n%@\n%@\n%@\n%@\n%@\n%@\n%@\n%d\n%d\n%d\n%d\n%d\n%d\n%d\n}\n",
+      @"RTCConfiguration: {\n%@\n%@\n%@\n%@\n%@\n%@\n%@\n%d\n%d\n%d\n%d\n%d\n%d\n%d\n%@\n}\n",
       _iceServers,
       [[self class] stringForTransportPolicy:_iceTransportPolicy],
       [[self class] stringForBundlePolicy:_bundlePolicy],
@@ -89,7 +94,8 @@
       _iceBackupCandidatePairPingInterval,
       _iceCandidatePoolSize,
       _shouldPruneTurnPorts,
-      _shouldPresumeWritableWhenFullyRelayed];
+      _shouldPresumeWritableWhenFullyRelayed,
+      _iceCheckMinInterval];
 }
 
 #pragma mark - Private
@@ -139,6 +145,10 @@
   nativeConfig->prune_turn_ports = _shouldPruneTurnPorts ? true : false;
   nativeConfig->presume_writable_when_fully_relayed =
       _shouldPresumeWritableWhenFullyRelayed ? true : false;
+  if (_iceCheckMinInterval != nil) {
+    nativeConfig->ice_check_min_interval =
+        rtc::Optional<int>(_iceCheckMinInterval.intValue);
+  }
 
   return nativeConfig.release();
 }

webrtc/sdk/objc/Framework/Headers/WebRTC/RTCConfiguration.h

@@ -104,6 +104,11 @@ RTC_EXPORT
  */
 @property(nonatomic, assign) BOOL shouldPresumeWritableWhenFullyRelayed;
 
+/** If set to non-nil, controls the minimal interval between consecutive ICE
+ *  check packets.
+ */
+@property(nonatomic, copy, nullable) NSNumber *iceCheckMinInterval;
+
 - (instancetype)init NS_DESIGNATED_INITIALIZER;
 
 @end