Move AsyncDns field trial to server-side control.

chrome/browser/net/async_dns_field_trial.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_NET_ASYNC_DNS_FIELD_TRIAL_H_
 #define CHROME_BROWSER_NET_ASYNC_DNS_FIELD_TRIAL_H_
 
-#include <string>
-
-class CommandLine;
-class Profile;
-
 namespace chrome_browser_net {
 
-// Configures the AsyncDns field trial as follows.
-// group A (async disabled): use CreateSystemHostResolver
-// group B (async enabled):  use CreateAsyncHostResolver
-// Returns true if should use CreateAsyncHostResolver.
+// Returns true if should set |HostResolver::Options::enable_async| to true.

[cbentzel, 2012/10/25 20:37:16]

This comment is a bit unclear.

Perhaps

Returns true when the async resolver should be used.

The groups that are assigned to it feel more like an implementation issue rather
than part of the interface.

+// Configures the AsyncDns field trial as follows:
+// groups AsyncDnsA and AsyncDnsB: return true,
+// groups SystemDnsA and SystemDnsB: return false,
+// otherwise (trial absent): return false.
 bool ConfigureAsyncDnsFieldTrial();
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_ASYNC_DNS_FIELD_TRIAL_H_