Parametrize variations server ping period.

chrome/browser/metrics/variations/variations_request_scheduler.cc

 // Copyright (c) 2013 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/metrics/variations/variations_request_scheduler.h"
 
+#include "base/strings/string_number_conversions.h"
+#include "components/variations/variations_associated_data.h"
+
 namespace chrome_variations {
 
+namespace {
+
+// Returns the time interval between variations seed fetches.
+base::TimeDelta GetFetchPeriod() {
+  // The fetch interval can be overridden by a variation param.
+  std::string period_min_str =
+      variations::GetVariationParamValue("VarationsServiceControl",
+                                         "fetch_period_min");
+  size_t period_min;
+  if (base::StringToSizeT(period_min_str, &period_min))
+    return base::TimeDelta::FromMinutes(period_min);
+
+  // The default fetch interval is every 5 hours.
+  return base::TimeDelta::FromHours(5);
+}
+
+}  // namespace
+
 VariationsRequestScheduler::VariationsRequestScheduler(
     const base::Closure& task) : task_(task) {
 }
 
 VariationsRequestScheduler::~VariationsRequestScheduler() {
 }
 
 void VariationsRequestScheduler::Start() {
-  // Time between regular seed fetches, in hours.
-  const int kFetchPeriodHours = 5;
   task_.Run();
-  timer_.Start(FROM_HERE, base::TimeDelta::FromHours(kFetchPeriodHours), task_);
+  timer_.Start(FROM_HERE, GetFetchPeriod(), task_);
 }
 
 void VariationsRequestScheduler::Reset() {
   if (timer_.IsRunning())
     timer_.Reset();
   one_shot_timer_.Stop();
 }
 
 void VariationsRequestScheduler::ScheduleFetchShortly() {
   // Reset the regular timer to avoid it triggering soon after.
@@ skipping 16 matching lines @@
 #if !defined(OS_ANDROID) && !defined(OS_IOS)
 // static
 VariationsRequestScheduler* VariationsRequestScheduler::Create(
     const base::Closure& task,
     PrefService* local_state) {
   return new VariationsRequestScheduler(task);
 }
 #endif  // !defined(OS_ANDROID) && !defined(OS_IOS)
 
 }  // namespace chrome_variations