Add a command line option to turn off retry attempts to resolve host

chrome/browser/io_thread.cc

 // Copyright (c) 2011 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 <vector>
 
 #include "base/command_line.h"
 #include "base/debug/leak_tracker.h"
@@ skipping 124 matching lines @@
     else if (trial->group() == parallel_9)
       parallelism = 9;
     else if (trial->group() == parallel_10)
       parallelism = 10;
     else if (trial->group() == parallel_14)
       parallelism = 14;
     else if (trial->group() == parallel_20)
       parallelism = 20;
   }
 
+  size_t retry_attempts = net::HostResolver::kDefaultRetryAttempts;
+
+  // Use the retry attempts override from the command-line, if any.
+  if (command_line.HasSwitch(switches::kHostResolverRetryAttempts)) {
+    std::string s =
+        command_line.GetSwitchValueASCII(switches::kHostResolverRetryAttempts);
+    // Parse the switch (it should be a non-negative integer).
+    int n;
+    if (base::StringToInt(s, &n) && n >= 0) {
+      retry_attempts = static_cast<size_t>(n);
+    } else {
+      LOG(ERROR) << "Invalid switch for host resolver retry attempts: " << s;
+    }
+  }
+
   net::HostResolver* global_host_resolver =
-      net::CreateSystemHostResolver(parallelism, net_log);
+      net::CreateSystemHostResolver(parallelism, retry_attempts, net_log);
 
   // Determine if we should disable IPv6 support.
   if (!command_line.HasSwitch(switches::kEnableIPv6)) {
     if (command_line.HasSwitch(switches::kDisableIPv6)) {
       global_host_resolver->SetDefaultAddressFamily(net::ADDRESS_FAMILY_IPV4);
     } else {
       net::HostResolverImpl* host_resolver_impl =
           global_host_resolver->GetAsHostResolverImpl();
       if (host_resolver_impl != NULL) {
         // Use probe to decide if support is warranted.
@@ skipping 517 matching lines @@
   system_params.network_delegate = globals_->system_network_delegate.get();
   system_params.net_log = net_log_;
   globals_->system_http_transaction_factory.reset(
       new net::HttpNetworkLayer(
           new net::HttpNetworkSession(system_params)));
   globals_->system_ftp_transaction_factory.reset(
       new net::FtpNetworkLayer(globals_->host_resolver.get()));
   globals_->system_request_context =
       ConstructSystemRequestContext(globals_, net_log_);
 }