Always use NonBlocking IO for UDP sockets on Windows.

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 68cfff7783b41855073cae1068f48e6b28bbc8b9..da624d9b8a860fc6921346ada5832044fbce058b 100644
--- a/media/cast/net/udp_transport.cc
+++ b/media/cast/net/udp_transport.cc
@@ -24,9 +24,6 @@ namespace cast {
 namespace {
 
 const char kOptionDscp[] = "DSCP";
-#if defined(OS_WIN)
-const char kOptionDisableNonBlockingIO[] = "disable_non_blocking_io";
-#endif
 const char kOptionSendBufferMinSize[] = "send_buffer_min_size";
 const char kOptionPacerMaxBurstSize[] = "pacer_max_burst_size";
 
@@ -139,15 +136,6 @@ void UdpTransport::SetDscp(net::DiffServCodePoint dscp) {
   next_dscp_value_ = dscp;
 }
 
-#if defined(OS_WIN)
-void UdpTransport::UseNonBlockingIO() {
-  DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
-  if (!udp_socket_)
-    return;
-  udp_socket_->UseNonBlockingIO();
-}
-#endif
-
 void UdpTransport::ScheduleReceiveNextPacket() {
   DCHECK(io_thread_proxy_->RunsTasksOnCurrentThread());
   if (!packet_receiver_.is_null() && !receive_pending_) {
@@ -307,11 +295,6 @@ void UdpTransport::SetUdpOptions(const base::DictionaryValue& options) {
     // priority over other traffic.
     SetDscp(net::DSCP_AF41);
   }
-#if defined(OS_WIN)
-  if (!options.HasKey(kOptionDisableNonBlockingIO)) {
-    UseNonBlockingIO();
-  }
-#endif
 }
 
 void UdpTransport::SetSendBufferSize(int32_t send_buffer_size) {