Support finch experiment WebRTC-UDPServerSocketAsync for Windows.

content/browser/renderer_host/p2p/socket_host_udp.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/p2p/socket_host_udp.h"
 
 #include "base/bind.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
@@ skipping 50 matching lines @@
       data(new net::IOBuffer(content.size())),
       size(content.size()),
       packet_options(options),
       id(id) {
   memcpy(data->data(), &content[0], size);
 }
 
 P2PSocketHostUdp::PendingPacket::~PendingPacket() {
 }
 
-P2PSocketHostUdp::P2PSocketHostUdp(IPC::Sender* message_sender,
-                                   int socket_id,
+P2PSocketHostUdp::P2PSocketHostUdp(IPC::Sender* message_sender, int socket_id,

[Sergey Ulanov, 2015/03/26 18:15:32]

Formatting was correct here. One argument per line in function definition. See
https://www.chromium.org/developers/coding-style

[John L. Miller, 2015/03/26 18:23:10]

Done.

                                    P2PMessageThrottler* throttler)
     : P2PSocketHost(message_sender, socket_id, P2PSocketHost::UDP),
-      socket_(
-          new net::UDPServerSocket(GetContentClient()->browser()->GetNetLog(),
-                                   net::NetLog::Source())),
       send_pending_(false),
       last_dscp_(net::DSCP_CS0),
       throttler_(throttler),
       send_buffer_size_(0) {
+  net::UDPServerSocket* socket = new net::UDPServerSocket(
+      GetContentClient()->browser()->GetNetLog(), net::NetLog::Source());
+#if defined(OS_WIN)
+  // If configured for finch experiment, use nonblocking IO.
+  if (base::FieldTrialList::FindFullName("WebRTC-UDPSocketNonBlockingIO") ==
+      "Enabled") {
+    socket->UseNonBlockingIO();
+  }
+#endif
+  socket_.reset(socket);
 }
 
 P2PSocketHostUdp::~P2PSocketHostUdp() {
   if (state_ == STATE_OPEN) {
     DCHECK(socket_.get());
     socket_.reset();
   }
 }
 
 void P2PSocketHostUdp::SetSendBufferSize() {
@@ skipping 279 matching lines @@
     case P2P_SOCKET_OPT_DSCP:
       return (net::OK == socket_->SetDiffServCodePoint(
           static_cast<net::DiffServCodePoint>(value))) ? true : false;
     default:
       NOTREACHED();
       return false;
   }
 }
 
 }  // namespace content