Add an IPC method for Blink to call RapporService::RecordSample()

components/rappor/rappor_service.cc

Index: components/rappor/rappor_service.cc
diff --git a/components/rappor/rappor_service.cc b/components/rappor/rappor_service.cc
index 7fc4fce7fb4e86f94b330d1e6a94df7927960137..c78ed207cc88c103e88441b6e85b2d3de692ba1d 100644
--- a/components/rappor/rappor_service.cc
+++ b/components/rappor/rappor_service.cc
@@ -5,6 +5,7 @@
 #include "components/rappor/rappor_service.h"
 
 #include "base/metrics/field_trial.h"
+#include "base/metrics/user_metrics.h"
 #include "base/stl_util.h"
 #include "base/time/time.h"
 #include "components/metrics/metrics_hashes.h"
@@ -105,6 +106,8 @@ void RapporService::Initialize(net::URLRequestContextGetter* request_context) {
                                                      request_context)),
                      internal::LoadCohort(pref_service_),
                      internal::LoadSecret(pref_service_));
+
+  EnableRecordFromUserMetrics();
 }
 
 void RapporService::Update(RecordingLevel recording_level, bool may_upload) {
@@ -183,6 +186,18 @@ void RapporService::OnLogInterval() {
   ScheduleNextLogRotation(base::TimeDelta::FromSeconds(kLogIntervalSeconds));
 }
 
+void RapporService::EnableRecordFromUserMetrics() {
+  user_metrics_callback_ = base::Bind(&RapporService::OnUserMetricsCallback,
+                                      base::Unretained(this));
+  base::AddRapporCallback(user_metrics_callback_);
+}
+
+void RapporService::OnUserMetricsCallback(
+    const std::string& metric,
+    const std::string& sample) {
+  RecordSample(metric, ETLD_PLUS_ONE_RAPPOR_TYPE, sample);
+}
+
 bool RapporService::ExportMetrics(RapporReports* reports) {
   if (metrics_map_.empty()) {
     DVLOG(2) << "metrics_map_ is empty.";