Only use core DRP proxies for media requests in network service

This implements the DRP logic for only using CORE proxies when proxying
RESOURCE_TYPE_MEDIA requests. A similar approach is used to
DataReductionProxyDelegate, which uses an MRUCache to associate URLs
to resource type during proxy resolution, since the ProxyDelegate only
has access to the URL.

Bug: 721403
Cq-Include-Trybots: luci.chromium.try:linux_mojo
Change-Id: Ib1c50dbc1344535e46c80b2d3a900dbb6b215141
Reviewed-on: https://chromium-review.googlesource.com/c/1274526
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: rajendrant <rajendrant@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600786}

components/data_reduction_proxy/content/common/data_reduction_proxy_url_loader_throttle.cc

@@ -27,6 +27,9 @@ void DataReductionProxyURLLoaderThrottle::WillStartRequest(
       request->url, static_cast<content::ResourceType>(request->resource_type),
       request->previews_state, &request->custom_proxy_pre_cache_headers);
   request->custom_proxy_post_cache_headers = post_cache_headers_;
+
+  if (request->resource_type == content::RESOURCE_TYPE_MEDIA)
+    request->custom_proxy_use_alternate_proxy_list = true;
 }
 
 }  // namespace data_reduction_proxy

components/data_reduction_proxy/content/common/data_reduction_proxy_url_loader_throttle_unittest.cc

@@ -62,4 +62,28 @@ TEST(DataReductionProxyURLLoaderThrottleTest,
   EXPECT_EQ(value, "bar");
 }
 
+TEST(DataReductionProxyURLLoaderThrottleTest, UseAlternateProxyList) {
+  DataReductionProxyURLLoaderThrottle throttle((net::HttpRequestHeaders()));
+  network::ResourceRequest request;
+  request.resource_type = content::RESOURCE_TYPE_MEDIA;
+  request.url = GURL("http://example.com");
+  bool defer = false;
+
+  throttle.WillStartRequest(&request, &defer);
+
+  EXPECT_TRUE(request.custom_proxy_use_alternate_proxy_list);
+}
+
+TEST(DataReductionProxyURLLoaderThrottleTest, DontUseAlternateProxyList) {
+  DataReductionProxyURLLoaderThrottle throttle((net::HttpRequestHeaders()));
+  network::ResourceRequest request;
+  request.resource_type = content::RESOURCE_TYPE_MAIN_FRAME;
+  request.url = GURL("http://example.com");
+  bool defer = false;
+
+  throttle.WillStartRequest(&request, &defer);
+
+  EXPECT_FALSE(request.custom_proxy_use_alternate_proxy_list);
+}
+
 }  // namespace data_reduction_proxy

components/data_reduction_proxy/core/browser/data_reduction_proxy_config.h

@@ -182,14 +182,14 @@ class DataReductionProxyConfig
   // Returns the current HTTP RTT estimate.
   base::Optional<base::TimeDelta> GetHttpRttEstimate() const;
 
- protected:
-  virtual base::TimeTicks GetTicksNow() const;
-
   // Updates the Data Reduction Proxy configurator with the current config.
   void UpdateConfigForTesting(bool enabled,
                               bool secure_proxies_allowed,
                               bool insecure_proxies_allowed);
 
+ protected:
+  virtual base::TimeTicks GetTicksNow() const;
+
   // Returns true if the default bypass rules should be added. Virtualized for
   // testing.
   virtual bool ShouldAddDefaultProxyBypassRules() const;

components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.h

@@ -122,6 +122,10 @@ class DataReductionProxyConfigServiceClient
       const net::ProxyServer& proxy_server,
       const net::LoadTimingInfo& load_timing_info);
 
+  void SetRemoteConfigAppliedForTesting(bool remote_config_applied) {
+    remote_config_applied_ = remote_config_applied;
+  }
+
  protected:
   // Retrieves the backoff entry object being used to throttle request failures.
   // Virtual for testing.

components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.cc

@@ -364,8 +364,24 @@ void DataReductionProxyIOData::OnProxyConfigUpdated() {
   if (!proxy_config_client_)
     return;
 
+  const auto proxies_for_http = config_->GetProxiesForHttp();
+
   auto config = network::mojom::CustomProxyConfig::New();
-  config->rules = configurator_->GetProxyConfig().proxy_rules();
+  config->rules =
+      configurator_
+          ->CreateProxyConfig(false /* probe_url_config */,
+                              config_->GetNetworkPropertiesManager(),
+                              proxies_for_http)
+          .proxy_rules();
+
+  // Set an alternate proxy list to be used for media requests which only
+  // contains proxies supporting the media resource type.
+  net::ProxyList media_proxies;
+  for (const auto& proxy : proxies_for_http) {
+    if (proxy.SupportsResourceType(ResourceTypeProvider::CONTENT_TYPE_MEDIA))
+      media_proxies.AddProxyServer(proxy.proxy_server());
+  }
+  config->alternate_proxy_list = media_proxies;
 
   net::EffectiveConnectionType type = GetEffectiveConnectionType();
   if (type > net::EFFECTIVE_CONNECTION_TYPE_OFFLINE) {

components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data_unittest.cc

@@ -13,7 +13,10 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/test/scoped_task_environment.h"
 #include "base/time/time.h"
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config.h"
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client_test_utils.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_configurator.h"
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_mutable_config_values.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_prefs.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_request_options.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.h"
@@ -37,6 +40,7 @@
 #include "services/network/test/test_network_quality_tracker.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+namespace data_reduction_proxy {
 namespace {
 // Used only to verify that a wrapped network delegate gets called.
 class CountingNetworkDelegate : public net::NetworkDelegateImpl {
@@ -62,10 +66,26 @@ class CountingNetworkDelegate : public net::NetworkDelegateImpl {
   int created_requests_;
 };
 
+std::string CreateEncodedConfig(
+    const std::vector<DataReductionProxyServer> proxy_servers) {
+  ClientConfig config;
+  config.set_session_key("session");
+  for (const auto& proxy_server : proxy_servers) {
+    ProxyServer* config_proxy =
+        config.mutable_proxy_config()->add_http_proxy_servers();
+    net::HostPortPair host_port_pair =
+        proxy_server.proxy_server().host_port_pair();
+    config_proxy->set_scheme(ProxyServer_ProxyScheme_HTTP);
+    config_proxy->set_host(host_port_pair.host());
+    config_proxy->set_port(host_port_pair.port());
+    config_proxy->set_type(proxy_server.IsCoreProxy()
+                               ? ProxyServer_ProxyType_CORE
+                               : ProxyServer_ProxyType_UNSPECIFIED_TYPE);
+  }
+  return EncodeConfig(config);
+}
 }  // namespace
 
-namespace data_reduction_proxy {
-
 class DataReductionProxyIODataTest : public testing::Test {
  public:
   DataReductionProxyIODataTest()
@@ -247,6 +267,8 @@ TEST_F(DataReductionProxyIODataTest, TestCustomProxyConfigClient) {
       client.config->post_cache_headers.HasHeader(chrome_proxy_header()));
   EXPECT_TRUE(
       client.config->pre_cache_headers.HasHeader(chrome_proxy_ect_header()));
+  // Alternate proxy list should be empty because there are no core proxies.
+  EXPECT_TRUE(client.config->alternate_proxy_list.IsEmpty());
 }
 
 TEST_F(DataReductionProxyIODataTest, TestCustomProxyConfigUpdatedOnECTChange) {
@@ -308,6 +330,8 @@ TEST_F(DataReductionProxyIODataTest,
 
 TEST_F(DataReductionProxyIODataTest,
        TestCustomProxyConfigUpdatedOnProxyChange) {
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kDisableDataReductionProxyWarmupURLFetch);
   DataReductionProxyIOData io_data(
       Client::UNKNOWN, prefs(),
       network::TestNetworkConnectionTracker::GetInstance(),
@@ -317,21 +341,61 @@ TEST_F(DataReductionProxyIODataTest,
   NetworkPropertiesManager network_properties_manager(
       base::DefaultClock::GetInstance(), prefs(),
       scoped_task_environment_.GetMainThreadTaskRunner());
-  auto proxy_server = net::ProxyServer::FromPacString("PROXY foo");
-  io_data.configurator()->Enable(
-      network_properties_manager,
-      {DataReductionProxyServer(proxy_server, ProxyServer_ProxyType_CORE)});
+  io_data.config()->SetNetworkPropertiesManagerForTesting(
+      &network_properties_manager);
+  io_data.config()->UpdateConfigForTesting(true, true, true);
+
+  auto proxy_server1 = net::ProxyServer::FromPacString("PROXY foo");
+  io_data.config_client()->ApplySerializedConfig(CreateEncodedConfig(
+      {DataReductionProxyServer(proxy_server1, ProxyServer_ProxyType_CORE)}));
 
   network::mojom::CustomProxyConfigClientPtrInfo client_ptr_info;
   TestCustomProxyConfigClient client(mojo::MakeRequest(&client_ptr_info));
   io_data.SetCustomProxyConfigClient(std::move(client_ptr_info));
   base::RunLoop().RunUntilIdle();
 
-  EXPECT_EQ(client.config->rules.proxies_for_http.Get(), proxy_server);
+  EXPECT_EQ(client.config->rules.proxies_for_http.Get(), proxy_server1);
+
+  auto proxy_server2 = net::ProxyServer::FromPacString("PROXY bar");
+  io_data.config_client()->SetRemoteConfigAppliedForTesting(false);
+  io_data.config_client()->ApplySerializedConfig(CreateEncodedConfig(
+      {DataReductionProxyServer(proxy_server2, ProxyServer_ProxyType_CORE)}));
+  base::RunLoop().RunUntilIdle();
+
+  EXPECT_EQ(client.config->rules.proxies_for_http.Get(), proxy_server2);
+}
+
+TEST_F(DataReductionProxyIODataTest,
+       TestCustomProxyConfigHasAlternateProxyListOfCoreProxies) {
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kDisableDataReductionProxyWarmupURLFetch);
+  DataReductionProxyIOData io_data(
+      Client::UNKNOWN, prefs(),
+      network::TestNetworkConnectionTracker::GetInstance(),
+      scoped_task_environment_.GetMainThreadTaskRunner(),
+      scoped_task_environment_.GetMainThreadTaskRunner(), false /* enabled */,
+      std::string() /* user_agent */, std::string() /* channel */);
+  NetworkPropertiesManager network_properties_manager(
+      base::DefaultClock::GetInstance(), prefs(),
+      scoped_task_environment_.GetMainThreadTaskRunner());
+  io_data.config()->SetNetworkPropertiesManagerForTesting(
+      &network_properties_manager);
+  io_data.config()->UpdateConfigForTesting(true, true, true);
 
-  io_data.configurator()->Disable();
+  auto core_proxy_server = net::ProxyServer::FromPacString("PROXY foo");
+  io_data.config_client()->ApplySerializedConfig(CreateEncodedConfig(
+      {DataReductionProxyServer(core_proxy_server, ProxyServer_ProxyType_CORE),
+       DataReductionProxyServer(net::ProxyServer::FromPacString("PROXY bar"),
+                                ProxyServer_ProxyType_UNSPECIFIED_TYPE)}));
+
+  network::mojom::CustomProxyConfigClientPtrInfo client_ptr_info;
+  TestCustomProxyConfigClient client(mojo::MakeRequest(&client_ptr_info));
+  io_data.SetCustomProxyConfigClient(std::move(client_ptr_info));
   base::RunLoop().RunUntilIdle();
-  EXPECT_TRUE(client.config->rules.proxies_for_http.IsEmpty());
+
+  net::ProxyList expected_proxy_list;
+  expected_proxy_list.SetSingleProxyServer(core_proxy_server);
+  EXPECT_TRUE(client.config->alternate_proxy_list.Equals(expected_proxy_list));
 }
 
 }  // namespace data_reduction_proxy

services/network/network_context_unittest.cc

@@ -3869,6 +3869,16 @@ class NetworkContextMockHostTest : public NetworkContextTest {
     EXPECT_TRUE(base_url.is_valid()) << base_url.possibly_invalid_spec();
     return base_url.Resolve(relative_url);
   }
+
+  net::ProxyServer ConvertToProxyServer(const net::EmbeddedTestServer& server) {
+    std::string base_url = server.base_url().spec();
+    // Remove slash from URL.
+    base_url.pop_back();
+    auto proxy_server =
+        net::ProxyServer::FromURI(base_url, net::ProxyServer::SCHEME_HTTP);
+    EXPECT_TRUE(proxy_server.is_valid()) << base_url;
+    return proxy_server;
+  }
 };
 
 TEST_F(NetworkContextMockHostTest, CustomProxyAddsHeaders) {
@@ -3887,10 +3897,8 @@ TEST_F(NetworkContextMockHostTest, CustomProxyAddsHeaders) {
       CreateContextWithParams(std::move(context_params));
 
   auto config = mojom::CustomProxyConfig::New();
-  std::string base_url = proxy_test_server.base_url().spec();
-  // Remove slash from URL.
-  base_url.pop_back();
-  config->rules.ParseFromString("http=" + base_url);
+  net::ProxyServer proxy_server = ConvertToProxyServer(proxy_test_server);
+  config->rules.ParseFromString("http=" + proxy_server.ToURI());
   config->pre_cache_headers.SetHeader("pre_foo", "pre_foo_value");
   config->post_cache_headers.SetHeader("post_foo", "post_foo_value");
   proxy_config_client->OnCustomProxyConfigUpdated(std::move(config));
@@ -3911,8 +3919,7 @@ TEST_F(NetworkContextMockHostTest, CustomProxyAddsHeaders) {
   EXPECT_EQ(response, base::JoinString({"post_bar_value", "post_foo_value",
                                         "pre_bar_value", "pre_foo_value"},
                                        "\n"));
-  EXPECT_EQ(client->response_head().proxy_server,
-            net::ProxyServer::FromURI(base_url, net::ProxyServer::SCHEME_HTTP));
+  EXPECT_EQ(client->response_head().proxy_server, proxy_server);
 }
 
 TEST_F(NetworkContextMockHostTest,
@@ -3932,10 +3939,8 @@ TEST_F(NetworkContextMockHostTest,
       CreateContextWithParams(std::move(context_params));
 
   auto config = mojom::CustomProxyConfig::New();
-  std::string base_url = proxy_test_server.base_url().spec();
-  // Remove slash from URL.
-  base_url.pop_back();
-  config->rules.ParseFromString("http=" + base_url);
+  net::ProxyServer proxy_server = ConvertToProxyServer(proxy_test_server);
+  config->rules.ParseFromString("http=" + proxy_server.ToURI());
   config->pre_cache_headers.SetHeader("foo", "bad");
   config->post_cache_headers.SetHeader("bar", "bad");
   proxy_config_client->OnCustomProxyConfigUpdated(std::move(config));
@@ -3952,8 +3957,7 @@ TEST_F(NetworkContextMockHostTest,
       mojo::BlockingCopyToString(client->response_body_release(), &response));
 
   EXPECT_EQ(response, base::JoinString({"bar_value", "foo_value"}, "\n"));
-  EXPECT_EQ(client->response_head().proxy_server,
-            net::ProxyServer::FromURI(base_url, net::ProxyServer::SCHEME_HTTP));
+  EXPECT_EQ(client->response_head().proxy_server, proxy_server);
 }
 
 TEST_F(NetworkContextMockHostTest, CustomProxyConfigHeadersAddedBeforeCache) {
@@ -3972,10 +3976,8 @@ TEST_F(NetworkContextMockHostTest, CustomProxyConfigHeadersAddedBeforeCache) {
       CreateContextWithParams(std::move(context_params));
 
   auto config = mojom::CustomProxyConfig::New();
-  std::string base_url = proxy_test_server.base_url().spec();
-  // Remove slash from URL.
-  base_url.pop_back();
-  config->rules.ParseFromString("http=" + base_url);
+  net::ProxyServer proxy_server = ConvertToProxyServer(proxy_test_server);
+  config->rules.ParseFromString("http=" + proxy_server.ToURI());
   config->pre_cache_headers.SetHeader("foo", "foo_value");
   config->post_cache_headers.SetHeader("bar", "bar_value");
   proxy_config_client->OnCustomProxyConfigUpdated(config->Clone());
@@ -3990,8 +3992,7 @@ TEST_F(NetworkContextMockHostTest, CustomProxyConfigHeadersAddedBeforeCache) {
       mojo::BlockingCopyToString(client->response_body_release(), &response));
 
   EXPECT_EQ(response, base::JoinString({"bar_value", "foo_value"}, "\n"));
-  EXPECT_EQ(client->response_head().proxy_server,
-            net::ProxyServer::FromURI(base_url, net::ProxyServer::SCHEME_HTTP));
+  EXPECT_EQ(client->response_head().proxy_server, proxy_server);
   EXPECT_FALSE(client->response_head().was_fetched_via_cache);
 
   // post_cache_headers should not break caching.
@@ -4016,8 +4017,7 @@ TEST_F(NetworkContextMockHostTest, CustomProxyConfigHeadersAddedBeforeCache) {
       mojo::BlockingCopyToString(client->response_body_release(), &response));
 
   EXPECT_EQ(response, base::JoinString({"new_bar", "new_foo"}, "\n"));
-  EXPECT_EQ(client->response_head().proxy_server,
-            net::ProxyServer::FromURI(base_url, net::ProxyServer::SCHEME_HTTP));
+  EXPECT_EQ(client->response_head().proxy_server, proxy_server);
   EXPECT_FALSE(client->response_head().was_fetched_via_cache);
 }
 
@@ -4037,10 +4037,8 @@ TEST_F(NetworkContextMockHostTest, CustomProxyRequestHeadersAddedBeforeCache) {
       CreateContextWithParams(std::move(context_params));
 
   auto config = mojom::CustomProxyConfig::New();
-  std::string base_url = proxy_test_server.base_url().spec();
-  // Remove slash from URL.
-  base_url.pop_back();
-  config->rules.ParseFromString("http=" + base_url);
+  net::ProxyServer proxy_server = ConvertToProxyServer(proxy_test_server);
+  config->rules.ParseFromString("http=" + proxy_server.ToURI());
   proxy_config_client->OnCustomProxyConfigUpdated(std::move(config));
   scoped_task_environment_.RunUntilIdle();
 
@@ -4055,8 +4053,7 @@ TEST_F(NetworkContextMockHostTest, CustomProxyRequestHeadersAddedBeforeCache) {
       mojo::BlockingCopyToString(client->response_body_release(), &response));
 
   EXPECT_EQ(response, base::JoinString({"bar_value", "foo_value"}, "\n"));
-  EXPECT_EQ(client->response_head().proxy_server,
-            net::ProxyServer::FromURI(base_url, net::ProxyServer::SCHEME_HTTP));
+  EXPECT_EQ(client->response_head().proxy_server, proxy_server);
   EXPECT_FALSE(client->response_head().was_fetched_via_cache);
 
   // custom_proxy_post_cache_headers should not break caching.
@@ -4077,8 +4074,7 @@ TEST_F(NetworkContextMockHostTest, CustomProxyRequestHeadersAddedBeforeCache) {
       mojo::BlockingCopyToString(client->response_body_release(), &response));
 
   EXPECT_EQ(response, base::JoinString({"new_bar", "new_foo"}, "\n"));
-  EXPECT_EQ(client->response_head().proxy_server,
-            net::ProxyServer::FromURI(base_url, net::ProxyServer::SCHEME_HTTP));
+  EXPECT_EQ(client->response_head().proxy_server, proxy_server);
   EXPECT_FALSE(client->response_head().was_fetched_via_cache);
 }
 
@@ -4128,10 +4124,8 @@ TEST_F(NetworkContextMockHostTest,
   mojom::NetworkContextParamsPtr context_params = CreateContextParams();
   // Set up a proxy to be used by the proxy config service.
   net::ProxyConfig proxy_config;
-  std::string base_url = proxy_test_server.base_url().spec();
-  // Remove slash from URL.
-  base_url.pop_back();
-  proxy_config.proxy_rules().ParseFromString("http=" + base_url);
+  proxy_config.proxy_rules().ParseFromString(
+      "http=" + ConvertToProxyServer(proxy_test_server).ToURI());
   context_params->initial_proxy_config = net::ProxyConfigWithAnnotation(
       proxy_config, TRAFFIC_ANNOTATION_FOR_TESTS);
 
@@ -4160,7 +4154,46 @@ TEST_F(NetworkContextMockHostTest,
 
   EXPECT_EQ(response, base::JoinString({"None", "None", "None", "None"}, "\n"));
   EXPECT_EQ(client->response_head().proxy_server,
-            net::ProxyServer::FromURI(base_url, net::ProxyServer::SCHEME_HTTP));
+            ConvertToProxyServer(proxy_test_server));
+}
+
+TEST_F(NetworkContextMockHostTest, CustomProxyUsesAlternateProxyList) {
+  net::EmbeddedTestServer invalid_server;
+  ASSERT_TRUE(invalid_server.Start());
+
+  net::EmbeddedTestServer proxy_test_server;
+  net::test_server::RegisterDefaultHandlers(&proxy_test_server);
+  ASSERT_TRUE(proxy_test_server.Start());
+
+  mojom::CustomProxyConfigClientPtr proxy_config_client;
+  mojom::NetworkContextParamsPtr context_params = CreateContextParams();
+  context_params->custom_proxy_config_client_request =
+      mojo::MakeRequest(&proxy_config_client);
+  std::unique_ptr<NetworkContext> network_context =
+      CreateContextWithParams(std::move(context_params));
+
+  auto config = mojom::CustomProxyConfig::New();
+  config->rules.ParseFromString("http=" +
+                                ConvertToProxyServer(invalid_server).ToURI());
+
+  config->alternate_proxy_list.AddProxyServer(
+      ConvertToProxyServer(proxy_test_server));
+  proxy_config_client->OnCustomProxyConfigUpdated(std::move(config));
+  scoped_task_environment_.RunUntilIdle();
+
+  ResourceRequest request;
+  request.url = GURL("http://does.not.resolve/echo");
+  request.custom_proxy_use_alternate_proxy_list = true;
+  std::unique_ptr<TestURLLoaderClient> client =
+      FetchRequest(request, network_context.get());
+  std::string response;
+  EXPECT_TRUE(
+      mojo::BlockingCopyToString(client->response_body_release(), &response));
+
+  // |invalid_server| has no handlers set up so would return an empty response.
+  EXPECT_EQ(response, "Echo");
+  EXPECT_EQ(client->response_head().proxy_server,
+            ConvertToProxyServer(proxy_test_server));
 }
 
 }  // namespace

services/network/network_service_proxy_delegate.cc

@@ -12,6 +12,10 @@
 namespace network {
 namespace {
 
+// The maximum size of the cache that contains the GURLs that should use
+// alternate proxy list.
+constexpr size_t kMaxCacheSize = 15;
+
 void GetAlternativeProxy(const GURL& url,
                          const net::ProxyRetryInfoMap& proxy_retry_info,
                          net::ProxyInfo* result) {
@@ -61,7 +65,8 @@ bool CheckProxyList(const net::ProxyList& proxy_list,
 
 NetworkServiceProxyDelegate::NetworkServiceProxyDelegate(
     mojom::CustomProxyConfigClientRequest config_client_request)
-    : binding_(this, std::move(config_client_request)) {}
+    : binding_(this, std::move(config_client_request)),
+      should_use_alternate_proxy_list_cache_(kMaxCacheSize) {}
 
 void NetworkServiceProxyDelegate::OnBeforeStartTransaction(
     net::URLRequest* request,
@@ -73,6 +78,9 @@ void NetworkServiceProxyDelegate::OnBeforeStartTransaction(
 
   auto* url_loader = URLLoader::ForRequest(*request);
   if (url_loader) {
+    if (url_loader->custom_proxy_use_alternate_proxy_list()) {
+      should_use_alternate_proxy_list_cache_.Put(request->url().spec(), true);
+    }
     headers->MergeFrom(url_loader->custom_proxy_pre_cache_headers());
   }
 }
@@ -115,8 +123,8 @@ void NetworkServiceProxyDelegate::OnResolveProxy(
     return;
 
   net::ProxyInfo proxy_info;
-  if (ApplyProxyConfigToProxyInfo(proxy_config_->rules, proxy_retry_info, url,
-                                  &proxy_info)) {
+  if (ApplyProxyConfigToProxyInfo(GetProxyRulesForURL(url), proxy_retry_info,
+                                  url, &proxy_info)) {
     DCHECK(!proxy_info.is_empty() && !proxy_info.is_direct());
     result->OverrideProxyList(proxy_info.proxy_list());
     GetAlternativeProxy(url, proxy_retry_info, result);
@@ -154,4 +162,15 @@ bool NetworkServiceProxyDelegate::EligibleForProxy(
          MayProxyURL(url) && net::HttpUtil::IsMethodIdempotent(method);
 }
 
+net::ProxyConfig::ProxyRules NetworkServiceProxyDelegate::GetProxyRulesForURL(
+    const GURL& url) const {
+  net::ProxyConfig::ProxyRules rules = proxy_config_->rules;
+  const auto iter = should_use_alternate_proxy_list_cache_.Peek(url.spec());
+  if (iter == should_use_alternate_proxy_list_cache_.end())
+    return rules;
+
+  rules.proxies_for_http = proxy_config_->alternate_proxy_list;
+  return rules;
+}
+
 }  // namespace network

services/network/network_service_proxy_delegate.h

@@ -6,6 +6,7 @@
 #define SERVICES_NETWORK_NETWORK_SERVICE_PROXY_DELEGATE_H_
 
 #include "base/component_export.h"
+#include "base/containers/mru_cache.h"
 #include "base/macros.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "net/base/proxy_delegate.h"
@@ -55,6 +56,9 @@ class COMPONENT_EXPORT(NETWORK_SERVICE) NetworkServiceProxyDelegate
                         const GURL& url,
                         const std::string& method) const;
 
+  // Get the proxy rules that apply to |url|.
+  net::ProxyConfig::ProxyRules GetProxyRulesForURL(const GURL& url) const;
+
   // mojom::CustomProxyConfigClient implementation:
   void OnCustomProxyConfigUpdated(
       mojom::CustomProxyConfigPtr proxy_config) override;
@@ -62,6 +66,8 @@ class COMPONENT_EXPORT(NETWORK_SERVICE) NetworkServiceProxyDelegate
   mojom::CustomProxyConfigPtr proxy_config_;
   mojo::Binding<mojom::CustomProxyConfigClient> binding_;
 
+  base::MRUCache<std::string, bool> should_use_alternate_proxy_list_cache_;
+
   DISALLOW_COPY_AND_ASSIGN(NetworkServiceProxyDelegate);
 };
 

services/network/public/cpp/network_ipc_param_traits.h

@@ -182,6 +182,7 @@ IPC_STRUCT_TRAITS_BEGIN(network::ResourceRequest)
   IPC_STRUCT_TRAITS_MEMBER(throttling_profile_id)
   IPC_STRUCT_TRAITS_MEMBER(custom_proxy_pre_cache_headers)
   IPC_STRUCT_TRAITS_MEMBER(custom_proxy_post_cache_headers)
+  IPC_STRUCT_TRAITS_MEMBER(custom_proxy_use_alternate_proxy_list)
 IPC_STRUCT_TRAITS_END()
 
 IPC_STRUCT_TRAITS_BEGIN(network::ResourceResponseInfo)

services/network/public/cpp/resource_request.h

@@ -237,6 +237,9 @@ struct COMPONENT_EXPORT(NETWORK_CPP_BASE) ResourceRequest {
   // that match the custom proxy config, and would otherwise be made direct.
   net::HttpRequestHeaders custom_proxy_pre_cache_headers;
   net::HttpRequestHeaders custom_proxy_post_cache_headers;
+
+  // Whether to use the alternate proxies set in the custom proxy config.
+  bool custom_proxy_use_alternate_proxy_list = false;
 };
 
 }  // namespace network

services/network/public/mojom/network_context.mojom

@@ -43,6 +43,10 @@ struct CustomProxyConfig {
   // http requests.
   ProxyRules rules;
 
+  // List of proxies that will be used if
+  // ResourceRequest::custom_proxy_use_alternate_proxy_list is set.
+  ProxyList alternate_proxy_list;
+
   // The custom proxy can set these headers in this config which will be added
   // to all requests using the proxy. This allows setting headers that may be
   // privacy/security sensitive which we don't want to send to the renderer.

services/network/url_loader.cc

@@ -323,6 +323,8 @@ URLLoader::URLLoader(
       first_auth_attempt_(true),
       custom_proxy_pre_cache_headers_(request.custom_proxy_pre_cache_headers),
       custom_proxy_post_cache_headers_(request.custom_proxy_post_cache_headers),
+      custom_proxy_use_alternate_proxy_list_(
+          request.custom_proxy_use_alternate_proxy_list),
       weak_ptr_factory_(this) {
   DCHECK(delete_callback_);
   if (!base::FeatureList::IsEnabled(features::kNetworkService)) {

services/network/url_loader.h

@@ -111,6 +111,10 @@ class COMPONENT_EXPORT(NETWORK_SERVICE) URLLoader
     return custom_proxy_post_cache_headers_;
   }
 
+  bool custom_proxy_use_alternate_proxy_list() const {
+    return custom_proxy_use_alternate_proxy_list_;
+  }
+
   // Gets the URLLoader associated with this request.
   static URLLoader* ForRequest(const net::URLRequest& request);
 
@@ -265,6 +269,7 @@ class COMPONENT_EXPORT(NETWORK_SERVICE) URLLoader
 
   net::HttpRequestHeaders custom_proxy_pre_cache_headers_;
   net::HttpRequestHeaders custom_proxy_post_cache_headers_;
+  bool custom_proxy_use_alternate_proxy_list_ = false;
 
   base::WeakPtrFactory<URLLoader> weak_ptr_factory_;
 

testing/buildbot/filters/mojo.fyi.network_browser_tests.filter

@@ -108,7 +108,6 @@
 -DataReductionProxyFallbackBrowsertest.FallbackProxyUsedWhenBlockZeroHeaderSent
 -DataReductionProxyFallbackBrowsertest.FallbackProxyUsedWhenBypassHeaderSent
 -DataReductionProxyFallbackBrowsertest.NoProxyUsedWhenBlockOnceHeaderSent
--DataReductionProxyResourceTypeBrowsertest.CoreProxyUsedForMedia
 
 # NOTE: if adding an exclusion for an existing failure (e.g. additional test for
 # feature X that is already not working), please add it beside the existing