Enable UMA log uploads for cellular networks.

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 18ec2e55bddae79355348dcc22bbf3e848231092..10f538a99e157f729e3214c6f9a31afc58a0674a 100644
--- a/components/metrics/metrics_service.cc
+++ b/components/metrics/metrics_service.cc
@@ -351,6 +351,7 @@ void MetricsService::InitializeMetricsRecordingState() {
   base::Closure callback = base::Bind(&MetricsService::StartScheduledUpload,
                                       self_ptr_factory_.GetWeakPtr());
   scheduler_.reset(new MetricsReportingScheduler(callback));
+  scheduler_->SetNetworkMetricsProvider(network_metrics_provider_);
 }
 
 void MetricsService::Start() {
@@ -1263,4 +1264,9 @@ void MetricsService::RecordCurrentState(PrefService* pref) {
                  base::Time::Now().ToTimeT());
 }
 
+void MetricsService::SetNetworkMetricsProvider() {
+  network_metrics_provider_ =
+      (metrics::NetworkMetricsProvider*)metrics_providers_.get().back();
+}
+
 }  // namespace metrics