Create Ukm ReportingService implementation.

components/metrics/data_use_tracker.cc

Index: components/metrics/data_use_tracker.cc
diff --git a/components/metrics/data_use_tracker.cc b/components/metrics/data_use_tracker.cc
index 6081facf5d6c068bdbf782c5fd05d7890e1b263b..cf211cbf28478f089bc72e58a27d492211fd1a7d 100644
--- a/components/metrics/data_use_tracker.cc
+++ b/components/metrics/data_use_tracker.cc
@@ -22,6 +22,34 @@ namespace {
 const int kDefaultUMAWeeklyQuotaBytes = 204800;
 const double kDefaultUMARatio = 0.05;
 
+struct CellDataUsePrefs {
+  const MetricsLogUploader::MetricServiceType service_type;
+  const char* service_name;
+  const char* pref_name;
+};
+
+const CellDataUsePrefs data_use_prefs[] = {
+    {MetricsLogUploader::UMA, "UMA", metrics::prefs::kUmaCellDataUse},
+    {MetricsLogUploader::UKM, "UKM", metrics::prefs::kUkmCellDataUse},
+};
+
+const char* GetPrefByServiceName(const std::string& service_name) {
+  for (const auto& pref : data_use_prefs) {
+    if (service_name == pref.service_name)
+      return pref.pref_name;
+  }
+  return nullptr;
+}
+
+const char* GetPrefByServiceType(
+    MetricsLogUploader::MetricServiceType service_type) {
+  for (const auto& pref : data_use_prefs) {
+    if (service_type == pref.service_type)
+      return pref.pref_name;
+  }
+  return nullptr;
+}
+
 }  // namespace
 
 DataUseTracker::DataUseTracker(PrefService* local_state)
@@ -42,7 +70,9 @@ std::unique_ptr<DataUseTracker> DataUseTracker::Create(
 // static
 void DataUseTracker::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterDictionaryPref(metrics::prefs::kUserCellDataUse);
-  registry->RegisterDictionaryPref(metrics::prefs::kUmaCellDataUse);
+  for (const auto& pref : data_use_prefs) {
+    registry->RegisterDictionaryPref(pref.pref_name);
+  }
 }
 
 void DataUseTracker::UpdateMetricsUsagePrefs(const std::string& service_name,
@@ -54,12 +84,18 @@ void DataUseTracker::UpdateMetricsUsagePrefs(const std::string& service_name,
     return;
 
   UpdateUsagePref(prefs::kUserCellDataUse, message_size);
-  if (service_name == "UMA")
-    UpdateUsagePref(prefs::kUmaCellDataUse, message_size);
+  const char* pref_name = GetPrefByServiceName(service_name);
+  if (pref_name)
+    UpdateUsagePref(pref_name, message_size);
 }
 
-bool DataUseTracker::ShouldUploadLogOnCellular(int log_bytes) {
+bool DataUseTracker::ShouldUploadLogOnCellular(
+    int log_bytes,
+    MetricsLogUploader::MetricServiceType service_type) {
   DCHECK(thread_checker_.CalledOnValidThread());
+  const char* pref_name = GetPrefByServiceType(service_type);
+  if (!pref_name)
+    return false;
 
   RemoveExpiredEntries();
 
@@ -67,7 +103,7 @@ bool DataUseTracker::ShouldUploadLogOnCellular(int log_bytes) {
   if (!GetUmaWeeklyQuota(&uma_weekly_quota_bytes))

[Alexei Svitkine (slow), 2017/03/24 18:27:21]

This function and variable names still say "uma". Please rename them.

Also, this is currently still using the same thresholds as UMA - I assume you're
OK with this for now, but please add TODOs around it, so we revise it. Also,
this is effectively doubling the allowed data use - since both UMA and UKM use
the same threshold but track their data separately. Mention this in a TODO.
....

Separately I also wonder if we should still track them together - e.g. both are
types of metrics and probably it makes sense to have an overall limit for Chrome
metrics data - rather than separate for UMA and UKM. Maybe it would be better to
start off that way until we discuss in a meeting with us and Rob and others? If
so, I suggest reverting the changes to this file for now in this CL other than
making UpdateMetricsUsagePrefs() check for both "UMA" and "UKM" - so their use
is tracked in the same pref for now.

     return true;
 
-  int uma_total_data_use = ComputeTotalDataUse(prefs::kUmaCellDataUse);
+  int uma_total_data_use = ComputeTotalDataUse(pref_name);
   int new_uma_total_data_use = log_bytes + uma_total_data_use;
   // If the new log doesn't increase the total UMA traffic to be above the
   // allowed quota then the log should be uploaded.
@@ -102,7 +138,9 @@ void DataUseTracker::UpdateUsagePref(const std::string& pref_name,
 
 void DataUseTracker::RemoveExpiredEntries() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  RemoveExpiredEntriesForPref(prefs::kUmaCellDataUse);
+  for (const auto& pref : data_use_prefs) {
+    RemoveExpiredEntriesForPref(pref.pref_name);
+  }
   RemoveExpiredEntriesForPref(prefs::kUserCellDataUse);
 }