Revert "Clean up dns prefetch code, and also port it."

chrome/browser/net/dns_global.cc

 // Copyright (c) 2006-2008 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 "chrome/browser/net/dns_global.h"
 
 #include <map>
 #include <string>
 
 #include "base/stats_counters.h"
@@ skipping 359 matching lines @@
 //------------------------------------------------------------------------------
 // This section intializes and tears down global DNS prefetch services.
 //------------------------------------------------------------------------------
 
 // Note: We have explicit permission to create the following global static
 // object (in opposition to Google style rules). By making it a static, we
 // can ensure its deletion.
 static PrefetchObserver dns_resolution_observer;
 
 void InitDnsPrefetch(PrefService* user_prefs) {
+  // Use a large shutdown time so that UI tests (that instigate lookups, and
+  // then try to shutdown the browser) don't instigate the CHECK about
+  // "some slaves have not finished"
+  const TimeDelta kAllowableShutdownTime(TimeDelta::FromSeconds(10));
   DCHECK(NULL == dns_master);
   if (!dns_master) {
-    dns_master = new DnsMaster();
+    dns_master = new DnsMaster(kAllowableShutdownTime);
     // We did the initialization, so we should prime the pump, and set up
     // the DNS resolution system to run.
     off_the_record_observer.Register();
 
     if (user_prefs) {
       bool enabled = user_prefs->GetBoolean(prefs::kDnsPrefetchingEnabled);
       EnableDnsPrefetch(enabled);
     }
 
     DLOG(INFO) << "DNS Prefetch service started";
 
     // Start observing real HTTP stack resolutions.
     net::AddDnsResolutionObserver(&dns_resolution_observer);
   }
 }
 
 void ShutdownDnsPrefetch() {
   DCHECK(NULL != dns_master);
-  delete dns_master;
+  DnsMaster* master = dns_master;
   dns_master = NULL;
+  if (master->ShutdownSlaves()) {
+    delete master;
+  } else {
+    // Leak instance if shutdown problem.
+    DCHECK(0);
+  }
 }
 
 static void DiscardAllPrefetchState() {
   if (!dns_master)
     return;
   dns_master->DiscardAllResults();
 }
 
 //------------------------------------------------------------------------------
 // Functions to handle saving of hostnames from one session to the next, to
@@ skipping 39 matching lines @@
   if (hostnames.size() > 0)
     DnsPrefetchMotivatedList(hostnames, DnsHostInfo::STARTUP_LIST_MOTIVATED);
   else  // Start a thread.
     DnsMotivatedPrefetch(std::string("www.google.com"),
                          DnsHostInfo::STARTUP_LIST_MOTIVATED);
 }
 
 
 }  // namespace chrome_browser_net