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

chrome/browser/net/dns_host_info.h

 // 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.
 
 // A DnsHostInfo object is used to store status of a Dns lookup of a specific
 // hostname.
-// It includes progress, from placement in the DnsMaster's queue, to resolution
-// by the DNS service as either FOUND or NO_SUCH_NAME.
+// It includes progress, from placement in the DnsMaster's queue, to assignment
+// to a slave, to resolution by the (blocking) DNS service as either FOUND or
+// NO_SUCH_NAME.
 
 #ifndef CHROME_BROWSER_NET_DNS_HOST_INFO_H_
 #define CHROME_BROWSER_NET_DNS_HOST_INFO_H_
 
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
 #include "base/time.h"
 #include "googleurl/src/gurl.h"
@@ skipping 27 matching lines @@
     // The following involve predictive prefetching, triggered by a navigation.
     // The referring_hostname_ is also set when these are used.
     // TODO(jar): Support STATIC_REFERAL_MOTIVATED API and integration.
     STATIC_REFERAL_MOTIVATED,  // External database suggested this resolution.
     LEARNED_REFERAL_MOTIVATED,  // Prior navigation taught us this resolution.
   };
 
   enum DnsProcessingState {
       // When processed by our prefetching system, the states are:
       PENDING,       // Constructor has completed.
-      QUEUED,        // In prefetch queue but not yet being resolved.
-      ASSIGNED,      // Currently being processed.
-      ASSIGNED_BUT_MARKED,  // Needs to be deleted as soon as it's resolved.
+      QUEUED,        // In prefetch queue but not yet assigned to a slave.
+      ASSIGNED,      // Currently being processed by a slave.
+      ASSIGNED_BUT_MARKED,  // Needs to be deleted as soon as slave is done.
       FOUND,         // DNS prefetch search completed.
       NO_SUCH_NAME,  // DNS prefetch search completed.
       // When processed by the network stack during navigation, the states are:
       STARTED,               // Resolution has begun for a navigation.
       FINISHED,              // Resolution has completed for a navigation.
       FINISHED_UNRESOLVED};  // No resolution found, so navigation will fail.
   static const base::TimeDelta kMaxNonNetworkDnsLookupDuration;
   // The number of OS cache entries we can guarantee(?) before cache eviction
   // might likely take place.
   static const int kMaxGuaranteedCacheSize = 50;
@@ skipping 115 matching lines @@
   std::string referring_hostname_;
 
   // We put these objects into a std::map, and hence we
   // need some "evil" constructors.
   // DISALLOW_COPY_AND_ASSIGN(DnsHostInfo);
 };
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_DNS_HOST_INFO_H_