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..619cf349778a5034228a9fc6bab5c7968ca36f32 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 +307,15 @@ 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(MetricsStateManager* state_manager,
+                               MetricsServiceClient* client,
+                               PrefService* local_state,
+                               base::Callback<void(bool*)> cellular_callback)
+    : MetricsService(state_manager, client, local_state) {
+  cellular_callback_ = cellular_callback;
 }
 
 MetricsService::~MetricsService() {
@@ -545,6 +556,10 @@ void MetricsService::PushExternalLog(const std::string& log) {
   log_manager_.StoreLog(log, MetricsLog::ONGOING_LOG);
 }
 
+base::WeakPtr<DataUseTracker> MetricsService::GetDataUseTracker() {
+  return data_use_tracker_->GetWeakPtr();
+}
+
 //------------------------------------------------------------------------------
 // private methods
 //------------------------------------------------------------------------------
@@ -866,7 +881,18 @@ 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.
+  bool is_cellular = false;
+  if (!cellular_callback_.is_null())
+    cellular_callback_.Run(&is_cellular);
+
+  if (is_cellular &&
+      data_use_tracker_->CanUploadUMALog(log_manager_.staged_log_hash().size()))
+    SendStagedLog();
+  else
+    scheduler_->UploadCancelled();
 }
 
 bool MetricsService::ProvidersHaveInitialStabilityMetrics() {