Add fine grain tracing to HostResolverImpl....

chrome/browser/io_thread.cc

 // Copyright (c) 2010 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/io_thread.h"
 #include "base/command_line.h"
 #include "base/leak_tracker.h"
 #include "base/logging.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/net/dns_global.h"
 #include "chrome/browser/net/url_fetcher.h"
 #include "chrome/common/chrome_switches.h"
 #include "net/base/fixed_host_resolver.h"
 #include "net/base/host_cache.h"
 #include "net/base/host_resolver.h"
+#include "net/base/host_resolver_impl.h"
 #include "net/url_request/url_request.h"
 
 namespace {
 
 net::HostResolver* CreateGlobalHostResolver() {
   net::HostResolver* global_host_resolver = NULL;
 
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   // The FixedHostResolver allows us to send all network requests through
@@ skipping 143 matching lines @@
 void IOThread::ChangedToOnTheRecordOnIOThread() {
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::IO));
 
   if (dns_master_) {
     // Destroy all evidence of our OTR session.
     dns_master_->DnsMaster::DiscardAllResults();
   }
 
   // Clear the host cache to avoid showing entries from the OTR session
   // in about:net-internals.
-  net::HostCache* host_cache = host_resolver_->GetHostCache();
-  if (host_cache)
-    host_cache->clear();
+  if (host_resolver_->IsHostResolverImpl()) {
+    net::HostCache* host_cache = static_cast<net::HostResolverImpl*>(
+        host_resolver_)->cache();
+    if (host_cache)
+      host_cache->clear();
+  }
 }