Adding PortAllocator option to support cases where sockets can't be bound.

webrtc/p2p/base/tcpport.cc

Index: webrtc/p2p/base/tcpport.cc
diff --git a/webrtc/p2p/base/tcpport.cc b/webrtc/p2p/base/tcpport.cc
index 79843d82de729eba851360513815e0334a5b7c99..92143020e3a7c68c46fb88614b12358f161e022d 100644
--- a/webrtc/p2p/base/tcpport.cc
+++ b/webrtc/p2p/base/tcpport.cc
@@ -96,23 +96,9 @@ TCPPort::TCPPort(rtc::Thread* thread,
       error_(0) {
   // TODO(mallinath) - Set preference value as per RFC 6544.
   // http://b/issue?id=7141794
-}
-
-bool TCPPort::Init() {
   if (allow_listen_) {
-    // Treat failure to create or bind a TCP socket as fatal.  This
-    // should never happen.

[Taylor Brandstetter, 2017/06/13 03:41:30]

"this should never happen" - juberti, Oct 13, 2013

-    socket_ = socket_factory()->CreateServerTcpSocket(
-        rtc::SocketAddress(ip(), 0), min_port(), max_port(),
-        false /* ssl */);
-    if (!socket_) {
-      LOG_J(LS_ERROR, this) << "TCP socket creation failed.";
-      return false;
-    }
-    socket_->SignalNewConnection.connect(this, &TCPPort::OnNewConnection);
-    socket_->SignalAddressReady.connect(this, &TCPPort::OnAddressReady);
+    TryCreateServerSocket();
   }
-  return true;
 }
 
 TCPPort::~TCPPort() {
@@ -274,6 +260,20 @@ void TCPPort::OnNewConnection(rtc::AsyncPacketSocket* socket,
   incoming_.push_back(incoming);
 }
 
+void TCPPort::TryCreateServerSocket() {
+  // Treat failure to create or bind a TCP socket as fatal.  This
+  // should never happen.
+  socket_ = socket_factory()->CreateServerTcpSocket(
+      rtc::SocketAddress(ip(), 0), min_port(), max_port(), false /* ssl */);
+  if (!socket_) {
+    LOG_J(LS_WARNING, this)
+        << "TCP server socket creation failed; continuing anyway.";
+    return;
+  }
+  socket_->SignalNewConnection.connect(this, &TCPPort::OnNewConnection);
+  socket_->SignalAddressReady.connect(this, &TCPPort::OnAddressReady);
+}
+
 rtc::AsyncPacketSocket* TCPPort::GetIncoming(
     const rtc::SocketAddress& addr, bool remove) {
   rtc::AsyncPacketSocket* socket = NULL;