Use Finch flag instead of command line for Expect CT reporting

chrome/browser/ssl/chrome_expect_ct_reporter_unittest.cc

 // Copyright 2016 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/ssl/chrome_expect_ct_reporter.h"
 
 #include <string>
 
 #include "base/base64.h"
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/json/json_reader.h"
 #include "base/values.h"
-#include "chrome/common/chrome_switches.h"
+#include "chrome/common/chrome_features.h"
 #include "net/base/test_data_directory.h"
 #include "net/ssl/signed_certificate_timestamp_and_status.h"
 #include "net/test/cert_test_util.h"
 #include "net/url_request/certificate_report_sender.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 namespace {
 
@@ skipping 218 matching lines @@
   const base::ListValue* report_invalid_scts = nullptr;
   ASSERT_TRUE(report_dict->GetList("invalid-scts", &report_invalid_scts));
   const base::ListValue* report_valid_scts = nullptr;
   ASSERT_TRUE(report_dict->GetList("valid-scts", &report_valid_scts));
 
   ASSERT_NO_FATAL_FAILURE(CheckReportSCTs(
       ssl_info.signed_certificate_timestamps, *report_unknown_scts,
       *report_invalid_scts, *report_valid_scts));
 }
 
+void EnableFeature() {
+  base::FeatureList::ClearInstanceForTesting();
+  std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
+  feature_list->InitializeFromCommandLine(features::kExpectCTReporting.name,
+                                          "");
+  base::FeatureList::SetInstance(std::move(feature_list));
+}
+
 }  // namespace
 
-// Test that no report is sent when the command line switch is not
-// enabled.
-TEST(ChromeExpectCTReporterTest, NoCommandLineSwitch) {
+// Test that no report is sent when the feature is not enabled.
+TEST(ChromeExpectCTReporterTest, FeatureDisabled) {
   TestCertificateReportSender* sender = new TestCertificateReportSender();
   net::TestURLRequestContext context;
   ChromeExpectCTReporter reporter(&context);
   reporter.report_sender_.reset(sender);
   EXPECT_TRUE(sender->latest_report_uri().is_empty());
   EXPECT_TRUE(sender->latest_serialized_report().empty());
 
   net::SSLInfo ssl_info;
   ssl_info.cert =
       net::ImportCertFromFile(net::GetTestCertsDirectory(), "ok_cert.pem");
   ssl_info.unverified_cert = net::ImportCertFromFile(
       net::GetTestCertsDirectory(), "localhost_cert.pem");
 
   net::HostPortPair host_port("example.test", 443);
   GURL report_uri("http://example-report.test");
 
   reporter.OnExpectCTFailed(host_port, report_uri, ssl_info);
   EXPECT_TRUE(sender->latest_report_uri().is_empty());
   EXPECT_TRUE(sender->latest_serialized_report().empty());
 }
 
 // Test that no report is sent if the report URI is empty.
 TEST(ChromeExpectCTReporterTest, EmptyReportURI) {
-  base::CommandLine::ForCurrentProcess()->AppendSwitch(
-      switches::kEnableExpectCTReporting);
+  EnableFeature();
   TestCertificateReportSender* sender = new TestCertificateReportSender();
   net::TestURLRequestContext context;
   ChromeExpectCTReporter reporter(&context);
   reporter.report_sender_.reset(sender);
   EXPECT_TRUE(sender->latest_report_uri().is_empty());
   EXPECT_TRUE(sender->latest_serialized_report().empty());
 
   reporter.OnExpectCTFailed(net::HostPortPair("example.test", 443), GURL(),
                             net::SSLInfo());
   EXPECT_TRUE(sender->latest_report_uri().is_empty());
   EXPECT_TRUE(sender->latest_serialized_report().empty());
 }
 
 // Test that a sent report has the right format.
 TEST(ChromeExpectCTReporterTest, SendReport) {
-  base::CommandLine::ForCurrentProcess()->AppendSwitch(
-      switches::kEnableExpectCTReporting);
+  EnableFeature();
   TestCertificateReportSender* sender = new TestCertificateReportSender();
   net::TestURLRequestContext context;
   ChromeExpectCTReporter reporter(&context);
   reporter.report_sender_.reset(sender);
   EXPECT_TRUE(sender->latest_report_uri().is_empty());
   EXPECT_TRUE(sender->latest_serialized_report().empty());
 
   net::SSLInfo ssl_info;
   ssl_info.cert =
       net::ImportCertFromFile(net::GetTestCertsDirectory(), "ok_cert.pem");
@@ skipping 35 matching lines @@
   net::HostPortPair host_port("example.test", 443);
   GURL report_uri("http://example-report.test");
 
   // Check that the report is sent and contains the correct information.
   reporter.OnExpectCTFailed(host_port, report_uri, ssl_info);
   EXPECT_EQ(report_uri, sender->latest_report_uri());
   EXPECT_FALSE(sender->latest_serialized_report().empty());
   ASSERT_NO_FATAL_FAILURE(CheckExpectCTReport(
       sender->latest_serialized_report(), host_port, ssl_info));
 }