Add support for single sample metrics.

components/metrics/single_value_histograms_provider.cc

+// Copyright 2017 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/single_value_histograms_provider.h"
+
+#include "components/metrics/single_value_counts_histogram.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
+namespace metrics {
+
+// static
+void SingleValueHistogramsProvider::Create(
+    mojom::SingleValueHistogramsProviderRequest request) {
+  // TODO(dalecurtis): Is strong binding what we want here? Seems like we'd
+  // prefer this is lazily created and available forever more to RPHI.
+  mojo::MakeStrongBinding(base::MakeUnique<SingleValueHistogramsProvider>(),
+                          std::move(request));
+}
+
+SingleValueHistogramsProvider::SingleValueHistogramsProvider() {
+  LOG(ERROR) << __func__;
+}
+
+SingleValueHistogramsProvider::~SingleValueHistogramsProvider() {
+  LOG(ERROR) << __func__;
+}
+
+void SingleValueHistogramsProvider::AcquireSingleValueCountsHistogram(
+    const std::string& name,
+    base::HistogramBase::Sample min,
+    base::HistogramBase::Sample max,
+    uint32_t bucket_count,
+    mojom::SingleValueCountsHistogramRequest request) {
+  mojo::MakeStrongBinding(base::MakeUnique<SingleValueCountsHistogram>(
+                              name, min, max, bucket_count),
+                          std::move(request));
+}
+
+}  // namespace metrics