Make WinsockInitSingleton explicitly leaky to avoid the AssertSingletonAllowed() dcheck.

net/base/winsock_init.cc

 // Copyright (c) 2011 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 <winsock2.h>
 
 #include "net/base/winsock_init.h"
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ skipping 12 matching lines @@
       // The first time WSAGetLastError is called, the delay load helper will
       // resolve the address with GetProcAddress and fixup the import.  If a
       // third party application hooks system functions without correctly
       // restoring the error code, it is possible that the error code will be
       // overwritten during delay load resolution.  The result of the first
       // call may be incorrect, so make sure the function is bound and future
       // results will be correct.
       WSAGetLastError();
     }
   }
-
-  ~WinsockInitSingleton() {

[gab, 2016/07/27 14:29:17]

On the bug when I said "delete the destructor" I meant to do so explicitly
(C++11 style) so that the compiler verifies the destructor is never invoked,
i.e. something like:

// The singleton instance has to be leaked (ref. comment on 
// |g_winsock_init_singleton| below).
~WinsockInitSingleton() = delete;

[gab, 2016/08/09 16:46:32]

ping, I think this would be cleaner, can you do this?

-    // Don't call WSACleanup() since the worker pool threads can continue to
-    // call getaddrinfo() after Winsock has shutdown, which can lead to crashes.
-  }
 };
 
-static base::LazyInstance<WinsockInitSingleton> g_winsock_init_singleton =
-    LAZY_INSTANCE_INITIALIZER;
+// Worker pool threads that use the Windows Sockets API may still be running at
+// shutdown. Leak instance and skip cleanup.
+static base::LazyInstance<WinsockInitSingleton>::Leaky
+    g_winsock_init_singleton = LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 namespace net {
 
 void EnsureWinsockInit() {
   g_winsock_init_singleton.Get();
 }
 
 }  // namespace net