Don't preresolve DNS if a fixed proxy configuration is in place.

net/proxy/proxy_service_unittest.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.h"
 
 #include <vector>
 
 #include "base/format_macros.h"
 #include "base/logging.h"
@@ skipping 3063 matching lines @@
   // since the PAC script poller experienced a failure.
   ProxyInfo info3;
   TestCompletionCallback callback3;
   rv = service.ResolveProxy(
       GURL("http://request3"), net::LOAD_NORMAL, &info3, callback3.callback(),
       NULL, NULL, BoundNetLog());
   EXPECT_EQ(OK, rv);
   EXPECT_TRUE(info3.is_direct());
 }
 
+// Test that the PAC script is not evaluated if a null callback is supplied.
+TEST_F(ProxyServiceTest, PACWithNullCallback) {
+  MockProxyConfigService* config_service =
+      new MockProxyConfigService("http://foopy/proxy.pac");
+
+  MockAsyncProxyResolver* resolver = new MockAsyncProxyResolver;
+
+  ProxyService service(config_service, resolver, NULL);
+
+  GURL url("http://www.google.com/");
+
+  ProxyInfo info;
+  info.UseDirect();
+  net::CompletionCallback null_callback;
+  ASSERT_TRUE(null_callback.is_null());
+  ProxyService::PacRequest* request = NULL;
+  CapturingBoundNetLog log;
+
+  int rv = service.ResolveProxy(
+      url, net::LOAD_NORMAL, &info, null_callback, &request, NULL, log.bound());
+  EXPECT_EQ(ERR_IO_PENDING, rv);
+
+  // No request should have been queued.
+  EXPECT_EQ(0u, resolver->pending_requests().size());
+
+  // |request| should not have been unmodified.
+  EXPECT_EQ(NULL, request);
+
+  // |info| should not have been modified.
+  EXPECT_TRUE(info.is_direct());
+}
+
+// Test that the PAC script is not evaluated if a null callback and request are
+// supplied.
+TEST_F(ProxyServiceTest, PACWithNullCallbackAndRequest) {
+  MockProxyConfigService* config_service =
+      new MockProxyConfigService("http://foopy/proxy.pac");
+
+  MockAsyncProxyResolver* resolver = new MockAsyncProxyResolver;
+
+  ProxyService service(config_service, resolver, NULL);
+
+  GURL url("http://www.google.com/");
+
+  ProxyInfo info;
+  info.UseDirect();
+  net::CompletionCallback null_callback;
+  ASSERT_TRUE(null_callback.is_null());
+  CapturingBoundNetLog log;
+
+  int rv = service.ResolveProxy(
+      url, net::LOAD_NORMAL, &info, null_callback, NULL, NULL, log.bound());
+  EXPECT_EQ(ERR_IO_PENDING, rv);
+
+  // No request should have been queued.
+  EXPECT_EQ(0u, resolver->pending_requests().size());
+
+  // |info| should not have been modified.
+  EXPECT_TRUE(info.is_direct());
+}
+
+// Test that synchronous results are returned correctly if a null callback is
+// supplied
+TEST_F(ProxyServiceTest, SynchronousResponseWithNullCallbackAndRequest) {
+  ProxyConfig config;
+  config.proxy_rules().ParseFromString("foopy1:8080");
+  config.set_auto_detect(false);
+
+  ProxyService service(
+      new MockProxyConfigService(config), new MockAsyncProxyResolver, NULL);
+
+  GURL url("http://www.google.com/");
+
+  ProxyInfo info;
+  net::CompletionCallback null_callback;
+  ASSERT_TRUE(null_callback.is_null());
+  CapturingBoundNetLog log;
+
+  int rv = service.ResolveProxy(
+      url, net::LOAD_NORMAL, &info, null_callback, NULL, NULL, log.bound());
+  EXPECT_EQ(OK, rv);
+  EXPECT_FALSE(info.is_direct());
+  EXPECT_EQ("foopy1", info.proxy_server().host_port_pair().host());
+}
+
 }  // namespace net