Implement host-based deletion for the hostname resolution cache.

chrome/browser/io_thread.h

 // 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.
 
 #ifndef CHROME_BROWSER_IO_THREAD_H_
 #define CHROME_BROWSER_IO_THREAD_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 204 matching lines @@
   void SetGlobalsForTesting(Globals* globals);
 
   net_log::ChromeNetLog* net_log();
 
   // Handles changing to On The Record mode, discarding confidential data.
   void ChangedToOnTheRecord();
 
   // Returns a getter for the URLRequestContext.  Only called on the UI thread.
   net::URLRequestContextGetter* system_url_request_context_getter();
 
-  // Clears the host cache.  Intended to be used to prevent exposing recently
+  // Clears the host cache. Intended to be used to prevent exposing recently
   // visited sites on about:net-internals/#dns and about:dns pages.  Must be
-  // called on the IO thread.
-  void ClearHostCache();
+  // called on the IO thread. If |host_filter| is not null, only hosts matched
+  // by it are deleted from the cache.
+  void ClearHostCache(
+      const base::Callback<bool(const std::string&)>& host_filter);
 
   const net::HttpNetworkSession::Params& NetworkSessionParams() const;
 
   base::TimeTicks creation_time() const;
 
   // Returns the callback for updating data use prefs.
   const metrics::UpdateUsagePrefCallbackType& GetMetricsDataUseForwarder();
 
   // Registers the |observer| for new STH notifications.
   void RegisterSTHObserver(net::ct::STHObserver* observer);
@@ skipping 152 matching lines @@
   // Callback for updating data use prefs which needs to be initialized on UI
   // thread and passed to |ChromeNetworkDelegate|.
   metrics::UpdateUsagePrefCallbackType metrics_data_use_forwarder_;
 
   base::WeakPtrFactory<IOThread> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IOThread);
 };
 
 #endif  // CHROME_BROWSER_IO_THREAD_H_