Set up Finch feature for network time policy browser test

chrome/browser/policy/policy_browsertest.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 <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "ash/accelerators/accelerator_controller_delegate_aura.h"
+#include "base/base_switches.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
@@ skipping 100 matching lines @@
 #include "components/security_interstitials/content/security_interstitial_page.h"
 #include "components/security_interstitials/core/controller_client.h"
 #include "components/strings/grit/components_strings.h"
 #include "components/translate/core/browser/language_state.h"
 #include "components/translate/core/browser/translate_infobar_delegate.h"
 #include "components/update_client/update_client.h"
 #include "components/update_client/update_client_errors.h"
 #include "components/update_client/url_request_post_interceptor.h"
 #include "components/user_prefs/user_prefs.h"
 #include "components/variations/service/variations_service.h"
+#include "components/variations/variations_switches.h"
 #include "components/version_info/version_info.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/child_process_data.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
 #include "content/public/browser/gpu_data_manager.h"
 #include "content/public/browser/interstitial_page.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_observer.h"
@@ skipping 4354 matching lines @@
   SetEmptyPolicy();
   // Policy not set.
   CheckSystemTimezoneAutomaticDetectionPolicyUnset();
   EXPECT_TRUE(CheckResolveTimezoneByGeolocation(true, false));
   EXPECT_TRUE(manager->TimeZoneResolverShouldBeRunningForTests());
 }
 #endif  // defined(OS_CHROMEOS)
 
 class NetworkTimePolicyTest : public PolicyTest {
  public:
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    command_line->AppendSwitchASCII(
+        switches::kEnableFeatures,
+        std::string(network_time::kNetworkTimeServiceQuerying.name) +
+            "<SSLNetworkTimeBrowserTestFieldTrial");

[Nico, 2017/05/24 17:43:03]

The < here is intentional, yes?

[estark, 2017/05/24 17:45:17]

Yeah, it's the --enable-features syntax (it's "GroupName>TrialName" or something
like that.)

Btw, I tested this by fix by removing the field trial from
fieldtrial_testing_config.json, observing that the test as I originally wrote it
failed, then observing that it passed with this SetUpCommandLine impl.

+    command_line->AppendSwitchASCII(
+        switches::kForceFieldTrials,
+        "SSLNetworkTimeBrowserTestFieldTrial/Enabled/");
+    command_line->AppendSwitchASCII(
+        variations::switches::kForceFieldTrialParams,
+        "SSLNetworkTimeBrowserTestFieldTrial.Enabled:FetchBehavior/"
+        "on-demand-only");
+  }
+
   // A request handler that returns a dummy response and counts the number of
   // times it is called.
   std::unique_ptr<net::test_server::HttpResponse> CountingRequestHandler(
       const net::test_server::HttpRequest& request) {
     net::test_server::BasicHttpResponse* response =
         new net::test_server::BasicHttpResponse();
     num_requests_++;
     response->set_code(net::HTTP_OK);
     response->set_content(
         ")]}'\n"
@@ skipping 42 matching lines @@
                POLICY_SCOPE_USER, POLICY_SOURCE_CLOUD,
                base::MakeUnique<base::Value>(true), nullptr);
   UpdateProviderPolicy(policies);
   ui_test_utils::NavigateToURL(browser(), https_server_expired_.GetURL("/"));
   interstitial_page = tab->GetInterstitialPage();
   ASSERT_TRUE(interstitial_page);
   EXPECT_EQ(1u, num_requests());
 }
 
 }  // namespace policy