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

chrome/browser/performance_monitor/database_unittest.cc

Index: chrome/browser/performance_monitor/database_unittest.cc
diff --git a/chrome/browser/performance_monitor/database_unittest.cc b/chrome/browser/performance_monitor/database_unittest.cc
index d6661fa02cdc3eeadcf94af22f907bc539598311..cb770c551b2c4f545383a5913bfa371626c7f14d 100644
--- a/chrome/browser/performance_monitor/database_unittest.cc
+++ b/chrome/browser/performance_monitor/database_unittest.cc
@@ -285,6 +285,24 @@ TEST_F(PerformanceMonitorDatabaseMetricTest, GetActiveMetrics) {
   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));

[Yoyo Zhou, 2012/08/02 11:54:57]

Just inline new TestingClock() here.

+  EXPECT_FALSE(db->GetRecentStatsForActivityAndMetric(METRIC_CPU_USAGE, &stat));
+}
+
 TEST_F(PerformanceMonitorDatabaseMetricTest, GetState) {
   std::string key("version");
   std::string value("1.0.0.0.1");