Allow MetricsProviders to request an initial stability log.

components/metrics/metrics_provider.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/metrics/metrics_provider.h"
+
+namespace metrics {
+
+MetricsProvider::MetricsProvider() {
+}
+
+MetricsProvider::~MetricsProvider() {
+}
+
+void MetricsProvider::OnDidCreateMetricsLog() {
+}
+
+void MetricsProvider::OnRecordingEnabled() {
+}
+
+void MetricsProvider::OnRecordingDisabled() {
+}
+
+void MetricsProvider::ProvideSystemProfileMetrics(
+    SystemProfileProto* system_profile_proto) {
+}
+
+bool MetricsProvider::HasStabilityMetrics() {
+  return false;
+}
+
+void MetricsProvider::ProvideStabilityMetrics(
+    SystemProfileProto* system_profile_proto) {
+}
+
+void MetricsProvider::ProvideGeneralMetrics(
+    ChromeUserMetricsExtension* uma_proto) {
+}
+
+}  // namespace metrics