Support experiment configurations with/without stability metrics.

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 5c9448987ab9b42348f2ed6a8b0743936542dacb..4e1eb054388b0731dab47fb76e39d36f0a692194 100644
--- a/components/metrics/metrics_service.cc
+++ b/components/metrics/metrics_service.cc
@@ -914,12 +914,14 @@ void MetricsService::SendNextLog() {
 
 bool MetricsService::ProvidersHaveInitialStabilityMetrics() {
   // Check whether any metrics provider has initial stability metrics.
-  for (MetricsProvider* provider : metrics_providers_) {
-    if (provider->HasInitialStabilityMetrics())
-      return true;
-  }
+  // All providers are queried (rather than stopping after the first "true"
+  // response) in case they do any kind of setup work in preparation for
+  // the later call to RecordInitialHistogramSnapshots().
+  bool has_stability_metrics = false;
+  for (MetricsProvider* provider : metrics_providers_)
+    has_stability_metrics |= provider->HasInitialStabilityMetrics();
 
-  return false;
+  return has_stability_metrics;
 }
 
 bool MetricsService::PrepareInitialStabilityLog(