Support experiment configurations with/without stability metrics.

components/metrics/file_metrics_provider.cc

Index: components/metrics/file_metrics_provider.cc
diff --git a/components/metrics/file_metrics_provider.cc b/components/metrics/file_metrics_provider.cc
index aa81a0cd1f02c55dd7255bc17711c9323213dafe..33874efdd8888e9432cff317f531b8d5ab3e5f9b 100644
--- a/components/metrics/file_metrics_provider.cc
+++ b/components/metrics/file_metrics_provider.cc
@@ -22,6 +22,7 @@
 #include "components/metrics/metrics_service.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
+#include "components/variations/variations_associated_data.h"
 
 namespace metrics {
 
@@ -471,6 +472,12 @@ void FileMetricsProvider::OnDidCreateMetricsLog() {
 bool FileMetricsProvider::HasInitialStabilityMetrics() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
+  // Check if there is an experiment that disables stability metrics.
+  std::string unreported = variations::GetVariationParamValueByFeature(
+      base::kPersistentHistogramsFeature, "send_unreported_metrics");
+  if (unreported == "no")
+    sources_for_previous_run_.clear();
+
   // Measure the total time spent checking all sources as well as the time
   // per individual file. This method is called during startup and thus blocks
   // the initial showing of the browser window so it's important to know the