Improve performance of proxy resolver by tracing DNS dependencies.

net/proxy/proxy_service_v8.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 "net/proxy/proxy_service_v8.h"
 
 #include "base/logging.h"
-#include "net/proxy/multi_threaded_proxy_resolver.h"
 #include "net/proxy/network_delegate_error_observer.h"
 #include "net/proxy/proxy_resolver.h"
-#include "net/proxy/proxy_resolver_js_bindings.h"
-#include "net/proxy/proxy_resolver_v8.h"
+#include "net/proxy/proxy_resolver_v8_tracing.h"
 #include "net/proxy/proxy_service.h"
-#include "net/proxy/sync_host_resolver_bridge.h"
 
 namespace net {
-namespace {
-
-// This factory creates V8ProxyResolvers with appropriate javascript bindings.
-class ProxyResolverFactoryForV8 : public ProxyResolverFactory {
- public:
-  // |async_host_resolver|, |io_loop| and |net_log| must remain
-  // valid for the duration of our lifetime.
-  // |async_host_resolver| will only be operated on |io_loop|.
-  // TODO(willchan): remove io_loop and replace it with origin_loop.
-  ProxyResolverFactoryForV8(HostResolver* async_host_resolver,
-                            MessageLoop* io_loop,
-                            base::MessageLoopProxy* origin_loop,
-                            NetLog* net_log,
-                            NetworkDelegate* network_delegate)
-      : ProxyResolverFactory(true /*expects_pac_bytes*/),
-        async_host_resolver_(async_host_resolver),
-        io_loop_(io_loop),
-        origin_loop_(origin_loop),
-        net_log_(net_log),
-        network_delegate_(network_delegate) {
-  }
-
-  virtual ProxyResolver* CreateProxyResolver() OVERRIDE {
-    // Create a synchronous host resolver wrapper that operates
-    // |async_host_resolver_| on |io_loop_|.
-    SyncHostResolverBridge* sync_host_resolver =
-        new SyncHostResolverBridge(async_host_resolver_, io_loop_);
-
-    NetworkDelegateErrorObserver* error_observer =
-        new NetworkDelegateErrorObserver(
-            network_delegate_, origin_loop_.get());
-
-    // ProxyResolverJSBindings takes ownership of |error_observer| and
-    // |sync_host_resolver|.
-    ProxyResolverJSBindings* js_bindings =
-        ProxyResolverJSBindings::CreateDefault(
-            sync_host_resolver, net_log_, error_observer);
-
-    // ProxyResolverV8 takes ownership of |js_bindings|.
-    return new ProxyResolverV8(js_bindings);
-  }
-
- private:
-  HostResolver* const async_host_resolver_;
-  MessageLoop* io_loop_;
-  scoped_refptr<base::MessageLoopProxy> origin_loop_;
-  NetLog* net_log_;
-  NetworkDelegate* network_delegate_;
-};
-
-}  // namespace
 
 // static
 ProxyService* CreateProxyServiceUsingV8ProxyResolver(
     ProxyConfigService* proxy_config_service,
-    size_t num_pac_threads,
     ProxyScriptFetcher* proxy_script_fetcher,
     DhcpProxyScriptFetcher* dhcp_proxy_script_fetcher,
     HostResolver* host_resolver,
     NetLog* net_log,
     NetworkDelegate* network_delegate) {
   DCHECK(proxy_config_service);
   DCHECK(proxy_script_fetcher);
   DCHECK(dhcp_proxy_script_fetcher);
   DCHECK(host_resolver);
 
-  if (num_pac_threads == 0)
-    num_pac_threads = ProxyService::kDefaultNumPacThreads;
-
-  ProxyResolverFactory* sync_resolver_factory =
-      new ProxyResolverFactoryForV8(
-          host_resolver,
-          MessageLoop::current(),
-          base::MessageLoopProxy::current(),
-          net_log,
-          network_delegate);
+  ProxyResolverErrorObserver* error_observer =
+      new NetworkDelegateErrorObserver(
+          network_delegate, base::MessageLoopProxy::current());
 
   ProxyResolver* proxy_resolver =
-      new MultiThreadedProxyResolver(sync_resolver_factory, num_pac_threads);
+      new ProxyResolverV8Tracing(host_resolver, error_observer, net_log);
 
   ProxyService* proxy_service =
       new ProxyService(proxy_config_service, proxy_resolver, net_log);
 
   // Configure fetchers to use for PAC script downloads and auto-detect.
   proxy_service->SetProxyScriptFetchers(proxy_script_fetcher,
                                         dhcp_proxy_script_fetcher);
 
   return proxy_service;
 }
 
 }  // namespace net