Create NetworkTimeTracker on startup for users in Finch experiment

components/network_time/network_time_tracker.cc

 // Copyright 2014 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 "components/network_time/network_time_tracker.h"
 
 #include <stdint.h>
 #include <string>
 #include <utility>
 
-#include "base/feature_list.h"
 #include "base/i18n/time_formatting.h"
 #include "base/json/json_reader.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/rand_util.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/tick_clock.h"
 #include "build/build_config.h"
 #include "components/client_update_protocol/ecdsa.h"
 #include "components/network_time/network_time_pref_names.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "components/variations/variations_associated_data.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_response_writer.h"
 #include "net/url_request/url_request_context_getter.h"
 
 namespace network_time {
 
+const base::Feature kNetworkTimeServiceQuerying{
+    "NetworkTimeServiceQuerying", base::FEATURE_DISABLED_BY_DEFAULT};
+
 namespace {
 
 // Time updates happen in two ways. First, other components may call
 // UpdateNetworkTime() if they happen to obtain the time securely.  This will
 // likely be deprecated in favor of the second way, which is scheduled time
 // queries issued by NetworkTimeTracker itself.
 //
 // On startup, the clock state may be read from a pref.  (This, too, may be
 // deprecated.)  After that, the time is checked every
 // |kCheckTimeIntervalSeconds|.  A "check" means the possibility, but not the
@@ skipping 40 matching lines @@
 const char kPrefNetworkTime[] = "network";
 
 // Time server's maximum allowable clock skew, in seconds.  (This is a property
 // of the time server that we happen to know.  It's unlikely that it would ever
 // be that badly wrong, but all the same it's included here to document the very
 // rough nature of the time service provided by this class.)
 const uint32_t kTimeServerMaxSkewSeconds = 10;
 
 const char kTimeServiceURL[] = "http://clients2.google.com/time/1/current";
 
-// Variations Service feature that enables network time service querying.
-const base::Feature kNetworkTimeServiceQuerying{
-    "NetworkTimeServiceQuerying", base::FEATURE_DISABLED_BY_DEFAULT};
-
 const char kVariationsServiceCheckTimeIntervalSeconds[] =
     "CheckTimeIntervalSeconds";
 const char kVariationsServiceRandomQueryProbability[] =
     "RandomQueryProbability";
 
 // This is an ECDSA prime256v1 named-curve key.
 const int kKeyVersion = 1;
 const uint8_t kKeyPubBytes[] = {
     0x30, 0x59, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02,
     0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07, 0x03,
@@ skipping 381 matching lines @@
   base::Time network_time;
   if (GetNetworkTime(&network_time, nullptr) != NETWORK_TIME_AVAILABLE) {
     return true;
   }
 
   // Otherwise, make the decision at random.
   return base::RandDouble() < RandomQueryProbability();
 }
 
 }  // namespace network_time