Cast: Fix crash in udp_transport

media/cast/net/udp_transport.cc

Index: media/cast/net/udp_transport.cc
diff --git a/media/cast/net/udp_transport.cc b/media/cast/net/udp_transport.cc
index f36b03444dbf59dca08e0b6e8d2d85b5c687b85d..95a8997b22b6c595ae07890baca2eb5c046f1979 100644
--- a/media/cast/net/udp_transport.cc
+++ b/media/cast/net/udp_transport.cc
@@ -75,6 +75,7 @@ void UdpTransport::StartReceiving(
         udp_socket_->AllowAddressReuse() < 0 ||
         udp_socket_->Bind(local_addr_) < 0) {
       udp_socket_->Close();
+      udp_socket_.reset();
       status_callback_.Run(TRANSPORT_SOCKET_ERROR);
       LOG(ERROR) << "Failed to bind local address.";
       return;
@@ -84,6 +85,7 @@ void UdpTransport::StartReceiving(
         udp_socket_->AllowAddressReuse() < 0 ||
         udp_socket_->Connect(remote_addr_) < 0) {
       udp_socket_->Close();
+      udp_socket_.reset();
       status_callback_.Run(TRANSPORT_SOCKET_ERROR);
       LOG(ERROR) << "Failed to connect to remote address.";
       return;
@@ -113,6 +115,8 @@ void UdpTransport::SetDscp(net::DiffServCodePoint dscp) {
 #if defined(OS_WIN)
 void UdpTransport::UseNonBlockingIO() {
   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
+  if (!udp_socket_)
+    return;
   udp_socket_->UseNonBlockingIO();
 }
 #endif
@@ -133,6 +137,8 @@ void UdpTransport::ReceiveNextPacket(int length_or_status) {
 
   if (packet_receiver_.is_null())
     return;
+  if (!udp_socket_)
+    return;
 
   // Loop while UdpSocket is delivering data synchronously.  When it responds
   // with a "pending" status, break and expect this method to be called back in
@@ -189,6 +195,8 @@ void UdpTransport::ReceiveNextPacket(int length_or_status) {
 
 bool UdpTransport::SendPacket(PacketRef packet, const base::Closure& cb) {
   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
+  if (!udp_socket_)
+    return true;
 
   // Increase byte count no matter the packet was sent or dropped.
   bytes_sent_ += packet->data.size();