Implement UMA log throttling for cellular connections

components/metrics/metrics_service.cc

Index: components/metrics/metrics_service.cc
diff --git a/components/metrics/metrics_service.cc b/components/metrics/metrics_service.cc
index c3ef7ec71d8dd9b69774d8c46a4a1ebb4196c61a..9428b636801e9a24d0811ddc0e80988c128a630f 100644
--- a/components/metrics/metrics_service.cc
+++ b/components/metrics/metrics_service.cc
@@ -149,6 +149,7 @@
 #include "base/tracked_objects.h"
 #include "base/values.h"
 #include "build/build_config.h"
+#include "components/metrics/data_use_tracker.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_log_manager.h"
 #include "components/metrics/metrics_log_uploader.h"
@@ -258,6 +259,7 @@ void MetricsService::RegisterPrefs(PrefRegistrySimple* registry) {
   DCHECK(IsSingleThreaded());
   MetricsStateManager::RegisterPrefs(registry);
   MetricsLog::RegisterPrefs(registry);
+  DataUseTracker::RegisterPrefs(registry);
 
   registry->RegisterInt64Pref(prefs::kInstallDate, 0);
 
@@ -305,6 +307,7 @@ MetricsService::MetricsService(MetricsStateManager* state_manager,
   int64_t install_date = local_state_->GetInt64(prefs::kInstallDate);
   if (install_date == 0)
     local_state_->SetInt64(prefs::kInstallDate, base::Time::Now().ToTimeT());
+  data_use_tracker_.reset(new DataUseTracker(local_state_));
 }
 
 MetricsService::~MetricsService() {
@@ -545,6 +548,12 @@ void MetricsService::PushExternalLog(const std::string& log) {
   log_manager_.StoreLog(log, MetricsLog::ONGOING_LOG);
 }
 
+UpdateUsagePrefCallbackType MetricsService::GetDataUseForwardingCallback() {
+  DCHECK(IsSingleThreaded());
+  return data_use_tracker_->GetDataUseForwardingCallback(
+      base::ThreadTaskRunnerHandle::Get());
+}
+
 //------------------------------------------------------------------------------
 // private methods
 //------------------------------------------------------------------------------
@@ -866,7 +875,16 @@ void MetricsService::SendNextLog() {
   }
   if (!log_manager_.has_staged_log())
     log_manager_.StageNextLogForUpload();
-  SendStagedLog();
+
+  // Proceed to stage the log for upload if log size satisfies cellular log
+  // upload constrains.
+  if (client_->IsUMACellularUploadLogicEnabled() &&
+      !data_use_tracker_->ShouldUploadLogOnCellular(
+          log_manager_.staged_log_hash().size())) {
+    scheduler_->UploadCancelled();
+  } else {
+    SendStagedLog();
+  }
 }
 
 bool MetricsService::ProvidersHaveInitialStabilityMetrics() {