Record policy usage statistics every 24 hours.

chrome/browser/policy/policy_statistics_collector.cc

Index: chrome/browser/policy/policy_statistics_collector.cc
diff --git a/chrome/browser/policy/policy_statistics_collector.cc b/chrome/browser/policy/policy_statistics_collector.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3d01564d5cff2a3fbe53268bc9d14a9a770dfa8e
--- /dev/null
+++ b/chrome/browser/policy/policy_statistics_collector.cc
@@ -0,0 +1,101 @@
+// Copyright (c) 2012 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/policy/policy_statistics_collector.h"
+
+#include <algorithm>
+#include <string>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/metrics/histogram.h"
+#include "base/task_runner.h"
+#include "chrome/browser/policy/policy_service.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/common/pref_names.h"
+#include "policy/policy_constants.h"
+
+namespace policy {
+
+const int PolicyStatisticsCollector::kStatisticsUpdateRate =
+    24 * 60 * 60 * 1000;  // 24 hours.
+
+PolicyStatisticsCollector::PolicyStatisticsCollector(
+    PolicyService* policy_service,
+    PrefService* prefs,
+    const scoped_refptr<base::TaskRunner>& task_runner)
+    : max_policy_id_(-1),
+      policy_service_(policy_service),
+      prefs_(prefs),
+      task_runner_(task_runner) {
+}
+
+PolicyStatisticsCollector::~PolicyStatisticsCollector() {
+}
+
+void PolicyStatisticsCollector::Initialize() {
+  using base::Time;
+  using base::TimeDelta;
+
+  TimeDelta update_rate = TimeDelta::FromMilliseconds(kStatisticsUpdateRate);
+  Time last_update = Time::FromInternalValue(
+      prefs_->GetInt64(prefs::kLastPolicyStatisticsUpdate));
+  TimeDelta delay = std::max(Time::Now() - last_update, TimeDelta::FromDays(0));
+  if (delay >= update_rate)
+    CollectStatistics();
+  else
+    ScheduleUpdate(update_rate - delay);
+}
+
+// static
+void PolicyStatisticsCollector::RegisterPrefs(PrefService* prefs) {
+  prefs->RegisterInt64Pref(prefs::kLastPolicyStatisticsUpdate, 0,
+                           PrefService::UNSYNCABLE_PREF);
+}
+
+void PolicyStatisticsCollector::RecordPolicyUse(int id) {
+  if (max_policy_id_ == -1) {
+    const policy::PolicyDefinitionList* policy_list =
+        policy::GetChromePolicyDefinitionList();
+    for (const policy::PolicyDefinitionList::Entry* policy = policy_list->begin;
+         policy != policy_list->end; ++policy) {
+      if (policy->id > max_policy_id_)
+        max_policy_id_ = policy->id;
+    }
+  }
+
+  // Set the boundary to be max policy id + 1. Note that this may decrease in
+  // future builds if the policy with maximum id is removed. This does not
+  // pose a problem.
+  DCHECK_LE(id, max_policy_id_);
+  UMA_HISTOGRAM_ENUMERATION("Enterprise.Policies", id, max_policy_id_ + 1);
+}
+
+void PolicyStatisticsCollector::CollectStatistics() {
+  const policy::PolicyDefinitionList* policy_list =
+      policy::GetChromePolicyDefinitionList();
+  const PolicyMap& policies = policy_service_->GetPolicies(POLICY_DOMAIN_CHROME,
+                                                           std::string());
+
+  // Collect statistics.
+  for (const policy::PolicyDefinitionList::Entry* policy = policy_list->begin;
+       policy != policy_list->end; ++policy) {
+    if (policies.Get(policy->name))
+      RecordPolicyUse(policy->id);
+  }
+
+  // Take care of next update.
+  prefs_->SetInt64(prefs::kLastPolicyStatisticsUpdate,
+                   base::Time::Now().ToInternalValue());
+  ScheduleUpdate(base::TimeDelta::FromMilliseconds(kStatisticsUpdateRate));
+}
+
+void PolicyStatisticsCollector::ScheduleUpdate(base::TimeDelta delay) {
+  update_callback_.Reset(base::Bind(
+      &PolicyStatisticsCollector::CollectStatistics,
+      base::Unretained(this)));
+  task_runner_->PostDelayedTask(FROM_HERE, update_callback_.callback(), delay);
+}
+
+}  // namespace policy