Turn on network time querying (on demand only) by default

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>
 
@@ skipping 18 matching lines @@
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_response_headers.h"
 #include "net/traffic_annotation/network_traffic_annotation.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 {
 
+// Network time queries are enabled on all desktop platforms except ChromeOS,
+// which uses tlsdated to set the system time.
+#if defined(OS_ANDROID) || defined(OS_CHROMEOS) || defined(OS_IOS)
 const base::Feature kNetworkTimeServiceQuerying{
     "NetworkTimeServiceQuerying", base::FEATURE_DISABLED_BY_DEFAULT};
+#else
+const base::Feature kNetworkTimeServiceQuerying{
+    "NetworkTimeServiceQuerying", base::FEATURE_ENABLED_BY_DEFAULT};
+#endif
 
 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
@@ skipping 53 matching lines @@
 const char kVariationsServiceRandomQueryProbability[] =
     "RandomQueryProbability";
 
 // This parameter can have three values:
 //
 // - "background-only": Time queries will be issued in the background as
 //   needed (when the clock loses sync), but on-demand time queries will
 //   not be issued (i.e. StartTimeFetch() will not start time queries.)
 //
 // - "on-demand-only": Time queries will not be issued except when
-//   StartTimeFetch() is called.
+//   StartTimeFetch() is called. This is the default value.
 //
 // - "background-and-on-demand": Time queries will be issued both in the
 //   background as needed and also on-demand.
 const char kVariationsServiceFetchBehavior[] = "FetchBehavior";
 
 // 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 174 matching lines @@
 NetworkTimeTracker::FetchBehavior NetworkTimeTracker::GetFetchBehavior() const {
   const std::string param = variations::GetVariationParamValueByFeature(
       kNetworkTimeServiceQuerying, kVariationsServiceFetchBehavior);
   if (param == "background-only") {
     return FETCHES_IN_BACKGROUND_ONLY;
   } else if (param == "on-demand-only") {
     return FETCHES_ON_DEMAND_ONLY;
   } else if (param == "background-and-on-demand") {
     return FETCHES_IN_BACKGROUND_AND_ON_DEMAND;
   }
-  return FETCH_BEHAVIOR_UNKNOWN;
+  return FETCHES_ON_DEMAND_ONLY;
 }
 
 void NetworkTimeTracker::SetTimeServerURLForTesting(const GURL& url) {
   server_url_ = url;
 }
 
 GURL NetworkTimeTracker::GetTimeServerURLForTesting() const {
   return server_url_;
 }
 
@@ skipping 316 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