Implement UMA log throttling for cellular connections

components/metrics/metrics_data_use_measurements.cc

+#include "components/metrics/metrics_data_use_measurements.h"
+
+#include <string>
+
+#include "base/strings/stringprintf.h"
+#include "components/metrics/metrics_pref_names.h"
+#include "components/prefs/scoped_user_pref_update.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace metrics{
+
+namespace {
+  static scoped_ptr<metrics::MetricsDataUseMeasurements> instance_;
+}
+
+//static
+void MetricsDataUseMeasurements::Initialize(PrefService* local_state) {
+  if (!instance_)
+    instance_.reset(new MetricsDataUseMeasurements(local_state));
+}
+
+//static
+MetricsDataUseMeasurements* MetricsDataUseMeasurements::GetInstance() {
+  return instance_.get();
+}
+
+MetricsDataUseMeasurements::MetricsDataUseMeasurements(PrefService* local_state)
+  :local_state_(local_state),
+  date_for_testing_(""),

[Alexei Svitkine (slow), 2016/03/18 22:23:30]

Nit: Can remove - std::string has a default ctor.

[gayane -on leave until 09-2017, 2016/03/29 16:06:20]

Done.

+  self_ptr_factory_(this) {}
+
+MetricsDataUseMeasurements::~MetricsDataUseMeasurements(){}
+
+void MetricsDataUseMeasurements::SetMeasurementDateForTesting(std::string date) {

[Alexei Svitkine (slow), 2016/03/18 22:23:30]

const std::string&

[gayane -on leave until 09-2017, 2016/03/29 16:06:20]

Done.

+  date_for_testing_ = date;
+}
+
+std::string MetricsDataUseMeasurements::GetCurrentMeasurementDate(){
+  if(date_for_testing_ != "")

[Alexei Svitkine (slow), 2016/03/18 22:23:30]

Nit: !.empty()

[gayane -on leave until 09-2017, 2016/03/29 16:06:20]

Done.

+    return date_for_testing_;
+
+  base::Time::Exploded today_exploded;
+  base::Time::Now().LocalMidnight().LocalExplode(&today_exploded);
+  return base::StringPrintf("%04d-%02d-%02d", today_exploded.year, today_exploded.month, today_exploded.day_of_month);
+}
+
+void MetricsDataUseMeasurements::UpdateMetricsUsagePrefs(const std::string& service_name, int message_size) {
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(&MetricsDataUseMeasurements::UpdateMetricsUsagePrefsOnUIThread, self_ptr_factory_.GetWeakPtr(), service_name, message_size));
+}
+
+void MetricsDataUseMeasurements::UpdateMetricsUsagePrefsOnUIThread(const std::string& service_name, int message_size) {
+  UpdateUsagePref(prefs::kUserCellDataUse, message_size);
+  if (service_name == "UMA")
+    UpdateUsagePref(prefs::kUmaCellDataUse, message_size);
+}
+
+void MetricsDataUseMeasurements::RemoveExpiredEntries() {
+  RemoveExpiredEntriesForPref(prefs::kUmaCellDataUse);
+  RemoveExpiredEntriesForPref(prefs::kUserCellDataUse);
+}
+
+void MetricsDataUseMeasurements::RemoveExpiredEntriesForPref(std::string pref_name) {
+  const base::DictionaryValue* user_pref_dict = local_state_->GetDictionary(pref_name);
+  if(!user_pref_dict)
+    return;
+  base::DictionaryValue user_pref_new_dict;
+  for (base::DictionaryValue::Iterator it(*user_pref_dict); !it.IsAtEnd();
+       it.Advance()) {
+    base::Time start_of_week = base::Time::Now().LocalMidnight() - base::TimeDelta::FromDays(7);
+    base::Time key_date;
+    base::Time::FromString(it.key().c_str(), &key_date);
+    if ( key_date >= start_of_week) {
+      user_pref_new_dict.Set(it.key(), it.value().CreateDeepCopy());
+    }
+  }
+  local_state_->Set(pref_name, user_pref_new_dict);
+}
+
+void MetricsDataUseMeasurements::UpdateUsagePref(const std::string& pref_name, int message_size) {
+  DictionaryPrefUpdate pref_updater(local_state_, pref_name);
+  int todays_traffic = 0;
+  std::string todays_key = GetCurrentMeasurementDate();
+  local_state_->GetDictionary(pref_name)->GetInteger(todays_key, &todays_traffic);
+  pref_updater->SetInteger(todays_key, todays_traffic + message_size);
+}
+
+bool MetricsDataUseMeasurements::CanUploadUMALog(int log_bytes) {
+  RemoveExpiredEntries();
+  int uma_total_data_use = TotalDataUse(prefs::kUmaCellDataUse);
+  if (log_bytes + uma_total_data_use <= GetUmaQouta())
+    return true;
+
+  int user_total_data_use = TotalDataUse(prefs::kUserCellDataUse);
+  return (log_bytes + uma_total_data_use)
+             /(double)(log_bytes + user_total_data_use)<= GetUmaRatio();
+}
+
+int MetricsDataUseMeasurements::TotalDataUse(std::string pref_name) {

[Alexei Svitkine (slow), 2016/03/18 22:23:30]

Nit: Compute*

[gayane -on leave until 09-2017, 2016/03/29 16:06:20]

Done.

+  int total_data_use = 0;
+  const base::DictionaryValue* pref_dict = local_state_->GetDictionary(pref_name);
+  if(!pref_dict)
+    return total_data_use;
+  for (base::DictionaryValue::Iterator it(*pref_dict); !it.IsAtEnd();

[Alexei Svitkine (slow), 2016/03/18 22:23:30]

What's stopping this from considering data outside the week?

[gayane -on leave until 09-2017, 2016/03/29 16:06:20]

nothing. its just this function should be called after RemoveExpiredEntries();
you think it should be called in this function?

+       it.Advance()) {
+    int value = 0;
+    it.value().GetAsInteger(&value);
+    total_data_use += value;
+  }
+  return total_data_use;
+}
+
+int MetricsDataUseMeasurements::GetUmaQouta() {
+  // TODO: read from experiment
+  return 200;
+}
+
+double MetricsDataUseMeasurements::GetUmaRatio() {
+  // TODO: read from experiment
+  return 0.05;
+}
+
+}// namespace metrics