Use Finch flag instead of command line for Expect CT reporting

chrome/browser/ssl/chrome_expect_ct_reporter.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_writer.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/values.h"
-#include "chrome/common/chrome_switches.h"
+#include "chrome/common/chrome_features.h"
 #include "net/url_request/certificate_report_sender.h"
 
 namespace {
 
 std::string TimeToISO8601(const base::Time& t) {
   base::Time::Exploded exploded;
   t.UTCExplode(&exploded);
   return base::StringPrintf(
       "%04d-%02d-%02dT%02d:%02d:%02d.%03dZ", exploded.year, exploded.month,
       exploded.day_of_month, exploded.hour, exploded.minute, exploded.second,
@@ skipping 84 matching lines @@
 
 ChromeExpectCTReporter::~ChromeExpectCTReporter() {}
 
 void ChromeExpectCTReporter::OnExpectCTFailed(
     const net::HostPortPair& host_port_pair,
     const GURL& report_uri,
     const net::SSLInfo& ssl_info) {
   if (report_uri.is_empty())
     return;
 
-  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableExpectCTReporting)) {
+  if (!base::FeatureList::IsEnabled(features::kExpectCTReporting))

[meacer, 2016/04/05 18:08:40]

This looks new, back in the days when I was young we used 
base::FieldTrialList::FindFullName.

[estark, 2016/04/05 18:10:39]

Yeah, I think it is new, and it's soooo nice!

     return;
-  }
 
   // TODO(estark): De-duplicate reports so that the same report isn't
   // sent too often in some period of time.
 
   base::DictionaryValue report;
   report.SetString("hostname", host_port_pair.host());
   report.SetInteger("port", host_port_pair.port());
   report.SetString("date-time", TimeToISO8601(base::Time::Now()));
   report.Set("served-certificate-chain",
              GetPEMEncodedChainAsList(ssl_info.unverified_cert.get()));
@@ skipping 25 matching lines @@
   report.Set("valid-scts", std::move(valid_scts));
 
   std::string serialized_report;
   if (!base::JSONWriter::Write(report, &serialized_report)) {
     LOG(ERROR) << "Failed to serialize Expect CT report";
     return;
   }
 
   report_sender_->Send(report_uri, serialized_report);
 }