Replace one use of sigslot with RoboCaller

The eventual goal is to replace sigslot entirely, but we need to
  start small, tread carefully, and evaluate how it works out.
  Also add a few more RoboCaller unit tests to cover the types we
  now use with RoboCaller.

Change-Id: I9a5814d1668a37546ea484ca88ec9c2be1913d25
Bug: webrtc:11943
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/184660
Commit-Queue: Lahiru Ginnaliya Gamathige <glahiru@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32266}

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",

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

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;
 

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(

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.";

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