diff --git a/pc/BUILD.gn b/pc/BUILD.gn
index 5cb362ce76..f59c1d7a88 100644
--- a/pc/BUILD.gn
+++ b/pc/BUILD.gn
@@ -112,6 +112,7 @@ rtc_library("rtc_pc_base") {
     "../rtc_base",
     "../rtc_base:checks",
     "../rtc_base:deprecation",
+    "../rtc_base:robo_caller",
     "../rtc_base:rtc_task_queue",
     "../rtc_base:stringutils",
     "../rtc_base/synchronization:mutex",
diff --git a/pc/jsep_transport_controller.cc b/pc/jsep_transport_controller.cc
index 98ad0000d0..4999f2ab04 100644
--- a/pc/jsep_transport_controller.cc
+++ b/pc/jsep_transport_controller.cc
@@ -1256,10 +1256,11 @@ void JsepTransportController::UpdateAggregateStates_n() {
   }
   if (ice_connection_state_ != new_connection_state) {
     ice_connection_state_ = new_connection_state;
-    invoker_.AsyncInvoke<void>(RTC_FROM_HERE, signaling_thread_,
-                               [this, new_connection_state] {
-                                 SignalIceConnectionState(new_connection_state);
-                               });
+
+    invoker_.AsyncInvoke<void>(
+        RTC_FROM_HERE, signaling_thread_, [this, new_connection_state] {
+          SignalIceConnectionState.Send(new_connection_state);
+        });
   }
 
   // Compute the current RTCIceConnectionState as described in
diff --git a/pc/jsep_transport_controller.h b/pc/jsep_transport_controller.h
index 190f740c7c..f3a92947a5 100644
--- a/pc/jsep_transport_controller.h
+++ b/pc/jsep_transport_controller.h
@@ -35,6 +35,7 @@
 #include "rtc_base/async_invoker.h"
 #include "rtc_base/constructor_magic.h"
 #include "rtc_base/ref_counted_object.h"
+#include "rtc_base/robo_caller.h"
 #include "rtc_base/third_party/sigslot/sigslot.h"
 
 namespace rtc {
@@ -197,10 +198,11 @@ class JsepTransportController : public sigslot::has_slots<> {
   // Else if all completed => completed,
   // Else if all connected => connected,
   // Else => connecting
-  sigslot::signal1<cricket::IceConnectionState> SignalIceConnectionState;
+  RoboCaller<cricket::IceConnectionState> SignalIceConnectionState;
 
   sigslot::signal1<PeerConnectionInterface::PeerConnectionState>
       SignalConnectionState;
+
   sigslot::signal1<PeerConnectionInterface::IceConnectionState>
       SignalStandardizedIceConnectionState;
 
diff --git a/pc/jsep_transport_controller_unittest.cc b/pc/jsep_transport_controller_unittest.cc
index 7bdba23c2d..40dc23e535 100644
--- a/pc/jsep_transport_controller_unittest.cc
+++ b/pc/jsep_transport_controller_unittest.cc
@@ -89,8 +89,10 @@ class JsepTransportControllerTest : public JsepTransportController::Observer,
   }
 
   void ConnectTransportControllerSignals() {
-    transport_controller_->SignalIceConnectionState.connect(
-        this, &JsepTransportControllerTest::OnConnectionState);
+    transport_controller_->SignalIceConnectionState.AddReceiver(
+        [this](cricket::IceConnectionState s) {
+          JsepTransportControllerTest::OnConnectionState(s);
+        });
     transport_controller_->SignalStandardizedIceConnectionState.connect(
         this, &JsepTransportControllerTest::OnStandardizedIceConnectionState);
     transport_controller_->SignalConnectionState.connect(
diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index 64898e207e..2b258cd5a9 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -685,8 +685,6 @@ bool PeerConnection::Initialize(
   transport_controller_.reset(new JsepTransportController(
       signaling_thread(), network_thread(), port_allocator_.get(),
       async_resolver_factory_.get(), config));
-  transport_controller_->SignalIceConnectionState.connect(
-      this, &PeerConnection::OnTransportControllerConnectionState);
   transport_controller_->SignalStandardizedIceConnectionState.connect(
       this, &PeerConnection::SetStandardizedIceConnectionState);
   transport_controller_->SignalConnectionState.connect(
@@ -704,6 +702,12 @@ bool PeerConnection::Initialize(
   transport_controller_->SignalIceCandidatePairChanged.connect(
       this, &PeerConnection::OnTransportControllerCandidateChanged);
 
+  transport_controller_->SignalIceConnectionState.AddReceiver(
+      [this](cricket::IceConnectionState s) {
+        RTC_DCHECK_RUN_ON(signaling_thread());
+        OnTransportControllerConnectionState(s);
+      });
+
   stats_.reset(new StatsCollector(this));
   stats_collector_ = RTCStatsCollector::Create(this);
 
@@ -3625,7 +3629,6 @@ PeerConnection::InitializePortAllocator_n(
                               "Disabled")) {
     port_allocator_flags &= ~(cricket::PORTALLOCATOR_ENABLE_IPV6);
   }
-
   if (configuration.disable_ipv6_on_wifi) {
     port_allocator_flags &= ~(cricket::PORTALLOCATOR_ENABLE_IPV6_ON_WIFI);
     RTC_LOG(LS_INFO) << "IPv6 candidates on Wi-Fi are disabled.";
diff --git a/rtc_base/robo_caller_unittest.cc b/rtc_base/robo_caller_unittest.cc
index 99719eaaf3..9330bb68a5 100644
--- a/rtc_base/robo_caller_unittest.cc
+++ b/rtc_base/robo_caller_unittest.cc
@@ -50,6 +50,32 @@ TEST(RoboCaller, ReferenceTest) {
   EXPECT_EQ(index, 2);
 }
 
+enum State {
+  kNew,
+  kChecking,
+};
+
+TEST(RoboCaller, SingleEnumValueTest) {
+  RoboCaller<State> c;
+  State s1 = kNew;
+  int index = 0;
+
+  c.AddReceiver([&index](State s) { index++; });
+  c.Send(s1);
+
+  EXPECT_EQ(index, 1);
+}
+
+TEST(RoboCaller, SingleEnumReferenceTest) {
+  RoboCaller<State&> c;
+  State s = kNew;
+
+  c.AddReceiver([](State& s) { s = kChecking; });
+  c.Send(s);
+
+  EXPECT_EQ(s, kChecking);
+}
+
 TEST(RoboCaller, ConstReferenceTest) {
   RoboCaller<int&> c;
   int i = 0;
@@ -166,6 +192,22 @@ TEST(RoboCaller, MultipleReceiverSendTest) {
 
   EXPECT_EQ(index, 5);
 }
+
+class A {
+ public:
+  void increment(int& i) const { i++; }
+};
+
+TEST(RoboCaller, MemberFunctionTest) {
+  RoboCaller<int&> c;
+  A a;
+  int index = 1;
+
+  c.AddReceiver([&a](int& i) { a.increment(i); });
+  c.Send(index);
+
+  EXPECT_EQ(index, 2);
+}
 // todo(glahiru): Add a test case to catch some error for Karl's first fix
 // todo(glahiru): Add a test for rtc::Bind
 // which used the following code in the Send