Adds a method to the Performance Monitor Database to fetch the most recent metric.

chrome/browser/performance_monitor/database_unittest.cc

 // Copyright (c) 2012 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 <algorithm>
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ skipping 267 matching lines @@
     db_->GetActiveMetrics(base::Time(), clock_->GetTime());
   std::sort(active_metrics.begin(), active_metrics.end());
 
   std::vector<const MetricDetails*> expected_metrics;
   expected_metrics.push_back(GetMetricDetails(METRIC_CPU_USAGE));
   expected_metrics.push_back(GetMetricDetails(METRIC_PRIVATE_MEMORY_USAGE));
   std::sort(expected_metrics.begin(), expected_metrics.end());
   EXPECT_EQ(expected_metrics, active_metrics);
 }
 
+TEST_F(PerformanceMonitorDatabaseMetricTest, GetRecentMetric) {
+  MetricInfo stat;
+  ASSERT_TRUE(db_->GetRecentStatsForActivityAndMetric(activity_,
+      METRIC_PRIVATE_MEMORY_USAGE, &stat));
+  EXPECT_EQ(3000000, stat.value);
+
+  ASSERT_TRUE(db_->GetRecentStatsForActivityAndMetric(METRIC_CPU_USAGE, &stat));
+  EXPECT_EQ(50.5, stat.value);
+
+  Database::Clock* clock2 = new TestingClock();
+  ScopedTempDir dir;
+  CHECK(dir.CreateUniqueTempDir());
+  scoped_ptr<Database> db = Database::Create(dir.path());
+  CHECK(db.get());
+  db->set_clock(scoped_ptr<Database::Clock>(clock2));
+  EXPECT_FALSE(db->GetRecentStatsForActivityAndMetric(METRIC_CPU_USAGE, &stat));
+}
+
 TEST_F(PerformanceMonitorDatabaseMetricTest, GetState) {
   std::string key("version");
   std::string value("1.0.0.0.1");
   db_->AddStateValue(key, value);
   EXPECT_EQ(db_->GetStateValue(key), value);
 }
 
 TEST_F(PerformanceMonitorDatabaseMetricTest, GetStateOverride) {
   std::string key("version");
   std::string value_1("1.0.0.0.0");
@@ skipping 68 matching lines @@
   base::Time end = clock_->GetTime();
   db_->AddMetric(kProcessChromeAggregate, METRIC_CPU_USAGE, std::string("21"));
   Database::MetricInfoVector stats =
       db_->GetStatsForActivityAndMetric(METRIC_CPU_USAGE, start, end);
   ASSERT_EQ(2u, stats.size());
   ASSERT_EQ(3, stats[0].value);
   ASSERT_EQ(9, stats[1].value);
 }
 
 }  // namespace performance_monitor