Add a field trial to enable out-of-process V8 pac.

chrome/browser/net/proxy_service_factory.cc

 // 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.
 
 #include "chrome/browser/net/proxy_service_factory.h"
 
 #include <string>
 
 #include "base/command_line.h"
+#include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/threading/thread.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/io_thread.h"
 #include "chrome/browser/net/pref_proxy_config_tracker_impl.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/log/net_log.h"
 #include "net/proxy/dhcp_proxy_script_fetcher_factory.h"
 #include "net/proxy/proxy_config_service.h"
@@ skipping 11 matching lines @@
 #include "net/proxy/proxy_resolver_v8.h"
 #endif
 
 #if !defined(OS_IOS) && !defined(OS_ANDROID)
 #include "chrome/browser/net/utility_process_mojo_proxy_resolver_factory.h"
 #include "net/proxy/proxy_service_mojo.h"
 #endif
 
 using content::BrowserThread;
 
+namespace {
+
+#if !defined(OS_ANDROID)
+bool EnableOutOfProcessV8Pac(const base::CommandLine& command_line) {
+  const std::string group_name =
+      base::FieldTrialList::FindFullName("OutOfProcessPac");
+
+  if (command_line.HasSwitch(switches::kDisableOutOfProcessPac))
+    return false;
+  if (command_line.HasSwitch(switches::kV8PacMojoOutOfProcess))
+    return true;
+  return group_name == "Enabled";
+}
+#endif  // !defined(OS_ANDROID)
+
+}  // namespace
+
 // static
 net::ProxyConfigService* ProxyServiceFactory::CreateProxyConfigService(
     PrefProxyConfigTracker* tracker) {
   // The linux gconf-based proxy settings getter relies on being initialized
   // from the UI thread.
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   scoped_ptr<net::ProxyConfigService> base_service;
 
 #if !defined(OS_CHROMEOS)
@@ skipping 86 matching lines @@
     net::DhcpProxyScriptFetcher* dhcp_proxy_script_fetcher;
 #if defined(OS_CHROMEOS)
     dhcp_proxy_script_fetcher =
         new chromeos::DhcpProxyScriptFetcherChromeos(context);
 #else
     net::DhcpProxyScriptFetcherFactory dhcp_factory;
     dhcp_proxy_script_fetcher = dhcp_factory.Create(context);
 #endif
 
 #if !defined(OS_ANDROID)
-    if (command_line.HasSwitch(switches::kV8PacMojoOutOfProcess)) {
+    // In-process Mojo PAC can only be set on the command line, so its presence
+    // should override other options.
+    if (command_line.HasSwitch(switches::kV8PacMojoInProcess)) {
+      proxy_service = net::CreateProxyServiceUsingMojoInProcess(
+          proxy_config_service, new net::ProxyScriptFetcherImpl(context),
+          dhcp_proxy_script_fetcher, context->host_resolver(), net_log,
+          network_delegate);
+    } else if (EnableOutOfProcessV8Pac(command_line)) {
       proxy_service = net::CreateProxyServiceUsingMojoFactory(
           UtilityProcessMojoProxyResolverFactory::GetInstance(),
           proxy_config_service, new net::ProxyScriptFetcherImpl(context),
           dhcp_proxy_script_fetcher, context->host_resolver(), net_log,
           network_delegate);
-    } else if (command_line.HasSwitch(switches::kV8PacMojoInProcess)) {
-      proxy_service = net::CreateProxyServiceUsingMojoInProcess(
-          proxy_config_service, new net::ProxyScriptFetcherImpl(context),
-          dhcp_proxy_script_fetcher, context->host_resolver(), net_log,
-          network_delegate);
     }
 #endif  // !defined(OS_ANDROID)
 
     if (!proxy_service) {
       proxy_service = net::CreateProxyServiceUsingV8ProxyResolver(
           proxy_config_service, new net::ProxyScriptFetcherImpl(context),
           dhcp_proxy_script_fetcher, context->host_resolver(), net_log,
           network_delegate);
     }
 #endif  // defined(OS_IOS)
   } else {
     proxy_service = net::ProxyService::CreateUsingSystemProxyResolver(
         proxy_config_service,
         num_pac_threads,
         net_log);
   }
 
   proxy_service->set_quick_check_enabled(quick_check_enabled);
 
   return proxy_service;
 }