diff --git a/pc/peer_connection.h b/pc/peer_connection.h
index 3d22bf4fd7..376dcc0c4e 100644
--- a/pc/peer_connection.h
+++ b/pc/peer_connection.h
@@ -210,13 +210,11 @@ class PeerConnection : public PeerConnectionInternal,
   void Close() override;
 
   // PeerConnectionInternal implementation.
-  rtc::Thread* network_thread() const override {
+  rtc::Thread* network_thread() const final {
     return factory_->network_thread();
   }
-  rtc::Thread* worker_thread() const override {
-    return factory_->worker_thread();
-  }
-  rtc::Thread* signaling_thread() const override {
+  rtc::Thread* worker_thread() const final { return factory_->worker_thread(); }
+  rtc::Thread* signaling_thread() const final {
     return factory_->signaling_thread();
   }
 
diff --git a/pc/peer_connection_factory.cc b/pc/peer_connection_factory.cc
index a2852bec52..9fd8b73d66 100644
--- a/pc/peer_connection_factory.cc
+++ b/pc/peer_connection_factory.cc
@@ -396,20 +396,6 @@ cricket::ChannelManager* PeerConnectionFactory::channel_manager() {
   return channel_manager_.get();
 }
 
-rtc::Thread* PeerConnectionFactory::signaling_thread() {
-  // This method can be called on a different thread when the factory is
-  // created in CreatePeerConnectionFactory().
-  return signaling_thread_;
-}
-
-rtc::Thread* PeerConnectionFactory::worker_thread() {
-  return worker_thread_;
-}
-
-rtc::Thread* PeerConnectionFactory::network_thread() {
-  return network_thread_;
-}
-
 std::unique_ptr<RtcEventLog> PeerConnectionFactory::CreateRtcEventLog_w() {
   RTC_DCHECK_RUN_ON(worker_thread_);
 
diff --git a/pc/peer_connection_factory.h b/pc/peer_connection_factory.h
index 99770878c6..40706cecd5 100644
--- a/pc/peer_connection_factory.h
+++ b/pc/peer_connection_factory.h
@@ -76,9 +76,15 @@ class PeerConnectionFactory : public PeerConnectionFactoryInterface {
   CreateSctpTransportInternalFactory();
 
   virtual cricket::ChannelManager* channel_manager();
-  virtual rtc::Thread* signaling_thread();
-  virtual rtc::Thread* worker_thread();
-  virtual rtc::Thread* network_thread();
+
+  rtc::Thread* signaling_thread() {
+    // This method can be called on a different thread when the factory is
+    // created in CreatePeerConnectionFactory().
+    return signaling_thread_;
+  }
+  rtc::Thread* worker_thread() { return worker_thread_; }
+  rtc::Thread* network_thread() { return network_thread_; }
+
   const Options& options() const { return options_; }
 
   MediaTransportFactory* media_transport_factory() {