Reland r59972: Eagerly set the IO loop used for OCSP.

net/ocsp/nss_ocsp.h

 // Copyright (c) 2009 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.
 
 #ifndef NET_OCSP_NSS_OCSP_H_
 #define NET_OCSP_NSS_OCSP_H_
 #pragma once
 
 class URLRequestContext;
 
 namespace net {
 
+// Sets the MessageLoop for OCSP to the current message loop.
+// This should be called before EnsureOCSPInit() if you want to
+// control the message loop for OCSP.
+void SetMessageLoopForOCSP();
+
 // Initializes OCSP handlers for NSS.  This must be called before any
 // certificate verification functions.  This function is thread-safe, and OCSP
 // handlers will only ever be initialized once.
 void EnsureOCSPInit();
 
 // Set URLRequestContext for OCSP handlers.
 void SetURLRequestContextForOCSP(URLRequestContext* request_context);
 URLRequestContext* GetURLRequestContextForOCSP();
 
 }  // namespace net
 
 #endif  // NET_OCSP_NSS_OCSP_H_