Expose audio_jitter_buffer_fast_accelerate config to objc wrapper

NOTRY=True
BUG=webrtc:6827

Review-Url: https://codereview.webrtc.org/2556553002
Cr-Commit-Position: refs/heads/master@{#15429}
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm b/webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm
index 4bd666c..bf602d7 100644
--- a/webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm
+++ b/webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm
@@ -28,6 +28,7 @@
 @synthesize candidateNetworkPolicy = _candidateNetworkPolicy;
 @synthesize continualGatheringPolicy = _continualGatheringPolicy;
 @synthesize audioJitterBufferMaxPackets = _audioJitterBufferMaxPackets;
+@synthesize audioJitterBufferFastAccelerate = _audioJitterBufferFastAccelerate;
 @synthesize iceConnectionReceivingTimeout = _iceConnectionReceivingTimeout;
 @synthesize iceBackupCandidatePairPingInterval =
     _iceBackupCandidatePairPingInterval;
@@ -58,6 +59,7 @@
     _continualGatheringPolicy =
         [[self class] continualGatheringPolicyForNativePolicy:nativePolicy];
     _audioJitterBufferMaxPackets = config.audio_jitter_buffer_max_packets;
+    _audioJitterBufferFastAccelerate = config.audio_jitter_buffer_fast_accelerate;
     _iceConnectionReceivingTimeout = config.ice_connection_receiving_timeout;
     _iceBackupCandidatePairPingInterval =
         config.ice_backup_candidate_pair_ping_interval;
@@ -72,7 +74,7 @@
 
 - (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}\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",
       _iceServers,
       [[self class] stringForTransportPolicy:_iceTransportPolicy],
       [[self class] stringForBundlePolicy:_bundlePolicy],
@@ -82,6 +84,7 @@
       [[self class]
           stringForContinualGatheringPolicy:_continualGatheringPolicy],
       _audioJitterBufferMaxPackets,
+      _audioJitterBufferFastAccelerate,
       _iceConnectionReceivingTimeout,
       _iceBackupCandidatePairPingInterval,
       _iceCandidatePoolSize,
@@ -113,6 +116,8 @@
   nativeConfig->continual_gathering_policy = [[self class]
       nativeContinualGatheringPolicyForPolicy:_continualGatheringPolicy];
   nativeConfig->audio_jitter_buffer_max_packets = _audioJitterBufferMaxPackets;
+  nativeConfig->audio_jitter_buffer_fast_accelerate =
+      _audioJitterBufferFastAccelerate  ? true : false;
   nativeConfig->ice_connection_receiving_timeout =
       _iceConnectionReceivingTimeout;
   nativeConfig->ice_backup_candidate_pair_ping_interval =