Move histogram_manager from components/metrics to components/cronet

components/cronet/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 "components/cronet/histogram_manager.h"
 
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/metrics/statistics_recorder.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) {
+TEST(HistogramManager, HistogramBucketFields) {
+  base::StatisticsRecorder::Initialize();

[mef, 2015/04/08 19:51:28]

I've added StatisticsRecorder::Initialize() and re-enabled the test.
It works on my machine. :)

   // 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);

[mef, 2015/04/08 19:51:27]

using LOCAL_HISTOGRAM_ENUMERATION results in empty deltas :( , but this is just
a presubmit WARNING. :)

 
   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 =
@@ skipping 14 matching lines @@
 
   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