Add UMA Histogram Manager to Cronet.

components/metrics/histogram_manager_unittest.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/histogram_manager.h"
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace metrics {
+
+// TODO(mef): crbug.com/441441. Move components/metrics/histogram_manager.*
+// files into components/android/cronet.
+// TODO(rtenneti): enable flaky HistogramBucketFields unit test.
+TEST(HistogramManager, DISABLED_HistogramBucketFields) {
+  // Capture histograms at the start of the test to avoid later GetDeltas()
+  // calls picking them up.
+  std::vector<uint8> data_init;
+  HistogramManager::GetInstance()->GetDeltas(&data_init);
+
+  // kNoFlags filter should record all histograms.
+  UMA_HISTOGRAM_ENUMERATION("UmaHistogramManager", 1, 2);
+
+  std::vector<uint8> data;
+  EXPECT_TRUE(HistogramManager::GetInstance()->GetDeltas(&data));
+  EXPECT_FALSE(data.empty());
+  ChromeUserMetricsExtension uma_proto;
+  EXPECT_TRUE(uma_proto.ParseFromArray(
+      reinterpret_cast<const char*>(&data[0]), data.size()));
+  EXPECT_FALSE(data.empty());
+
+  const HistogramEventProto& histogram_proto =
+      uma_proto.histogram_event(uma_proto.histogram_event_size() - 1);
+  ASSERT_EQ(1, histogram_proto.bucket_size());
+  EXPECT_LE(0, histogram_proto.bucket(0).min());
+  EXPECT_LE(2, histogram_proto.bucket(0).max());
+  EXPECT_EQ(1, histogram_proto.bucket(0).count());
+
+  UMA_HISTOGRAM_ENUMERATION("UmaHistogramManager2", 2, 3);
+  std::vector<uint8> data2;
+  EXPECT_TRUE(HistogramManager::GetInstance()->GetDeltas(&data2));
+  EXPECT_FALSE(data2.empty());
+  ChromeUserMetricsExtension uma_proto2;
+  EXPECT_TRUE(uma_proto2.ParseFromArray(
+      reinterpret_cast<const char*>(&data2[0]), data2.size()));
+  EXPECT_FALSE(data2.empty());
+
+  const HistogramEventProto& histogram_proto2 =
+      uma_proto2.histogram_event(uma_proto2.histogram_event_size() - 1);
+  ASSERT_EQ(1, histogram_proto2.bucket_size());
+  EXPECT_LE(0, histogram_proto2.bucket(0).min());
+  EXPECT_LE(3, histogram_proto2.bucket(0).max());
+  EXPECT_EQ(1, histogram_proto2.bucket(0).count());
+}
+
+}  // namespace metrics