Performance monitor stats gathering.

chrome/browser/performance_monitor/performance_monitor_browsertest.cc

Index: chrome/browser/performance_monitor/performance_monitor_browsertest.cc
diff --git a/chrome/browser/performance_monitor/performance_monitor_browsertest.cc b/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
index dedcf9993e4fd27b8d1541d3c8675194f044e98f..af748c7c6304c0803bf56b7cd8a5c5d3c8533a1c 100644
--- a/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
+++ b/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
@@ -16,6 +16,7 @@
 #include "chrome/browser/extensions/unpacked_installer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/browser_tabstrip.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/chrome_paths.h"
@@ -30,6 +31,10 @@ using extensions::Extension;
 using performance_monitor::Event;
 
 namespace {
+
+// Used in PerformanceMonitorBrowserTest.GatherStatistics to consume CPU cycles.
+int kSpinCount = 1000000000;
+
 // Helper struct to store the information of an extension; this is needed if the
 // pointer to the extension ever becomes invalid (e.g., if we uninstall the
 // extension).
@@ -171,6 +176,34 @@ class PerformanceMonitorBrowserTest : public ExtensionBrowserTest {
     return events;
   }
 
+  // Retrieves stats from the database, given |activity| and |metric|. Does the
+  // retrieval on a background thread.
+  Database::MetricInfoVector GetStatsForActivityAndMetric(
+      const std::string& activity,
+      const std::string& metric) {
+    Database::MetricInfoVector stats;
+    content::BrowserThread::PostBlockingPoolSequencedTask(
+        Database::kDatabaseSequenceToken,
+        FROM_HERE,
+        base::Bind(&PerformanceMonitorBrowserTest::
+                       GetStatsForActivityAndMetricOnBackgroundThread,
+                   base::Unretained(this),
+                   activity,
+                   metric,
+                   &stats));
+
+    content::BrowserThread::GetBlockingPool()->FlushForTesting();
+    return stats;
+  }
+
+  void GetStatsForActivityAndMetricOnBackgroundThread(
+      const std::string& activity,
+      const std::string& metric,
+      Database::MetricInfoVector* stats) {
+    *stats = performance_monitor_->database()->
+        GetStatsForActivityAndMetric(activity, metric);
+  }
+
   // A handle for inserting a state value into the database, which must be done
   // on the background thread. This is useful for mocking up a scenario in which
   // the database has prior data stored. We mock synchronicity with
@@ -395,6 +428,75 @@ IN_PROC_BROWSER_TEST_F(PerformanceMonitorBrowserTest, NewVersionEvent) {
   ASSERT_EQ(version_string, current_version);
 }
 
+IN_PROC_BROWSER_TEST_F(PerformanceMonitorBrowserTest, GatherStatistics) {
+  content::BrowserThread::PostBlockingPoolSequencedTask(
+      Database::kDatabaseSequenceToken,
+      FROM_HERE,
+      base::Bind(&PerformanceMonitor::GatherStatisticsOnBackgroundThread,
+                 base::Unretained(performance_monitor())));
+
+  content::BrowserThread::GetBlockingPool()->FlushForTesting();
+
+  // Gather CPU usage. No stats should be recorded because this was the first
+  // call to GatherStatistics.
+  Database::MetricInfoVector stats = GetStatsForActivityAndMetric(
+      performance_monitor::kProcessChromeAggregate,
+      performance_monitor::kMetricCPUUsage);
+  ASSERT_EQ(0u, stats.size());
+
+  // Gather private memory usage.
+  stats = GetStatsForActivityAndMetric(
+      performance_monitor::kProcessChromeAggregate,
+      performance_monitor::kMetricPrivateMemoryUsage);
+  ASSERT_EQ(1u, stats.size());
+  EXPECT_GT(stats[0].value, 0);
+
+  // Gather shared memory usage.
+  stats = GetStatsForActivityAndMetric(
+      performance_monitor::kProcessChromeAggregate,
+      performance_monitor::kMetricSharedMemoryUsage);
+  ASSERT_EQ(1u, stats.size());
+  EXPECT_GT(stats[0].value, 0);
+
+  // TODO(mwrosen) something less barbaric?
+  // Spin for a while, so CPU usage isn't 0.
+  int i = 0;
+  for (; i < kSpinCount; ++i) {
+  }
+  ASSERT_EQ(kSpinCount, i);
+
+  content::BrowserThread::PostBlockingPoolSequencedTask(
+      Database::kDatabaseSequenceToken,
+      FROM_HERE,
+      base::Bind(&PerformanceMonitor::GatherStatisticsOnBackgroundThread,
+                 base::Unretained(performance_monitor())));
+
+  content::BrowserThread::GetBlockingPool()->FlushForTesting();
+
+  // Gather CPU usage a second time and verify a stat was recorded.
+  stats = GetStatsForActivityAndMetric(
+      performance_monitor::kProcessChromeAggregate,
+      performance_monitor::kMetricCPUUsage);
+  ASSERT_EQ(1u, stats.size());
+  EXPECT_GT(stats[0].value, 0);
+
+  // Gather private memory usage a second time and verify a second stat was
+  // recorded.
+  stats = GetStatsForActivityAndMetric(
+      performance_monitor::kProcessChromeAggregate,
+      performance_monitor::kMetricPrivateMemoryUsage);
+  ASSERT_EQ(2u, stats.size());
+  EXPECT_GT(stats[1].value, 0);
+
+  // Gather shared memory usage a second time and verify a second stat was
+  // recorded.
+  stats = GetStatsForActivityAndMetric(
+      performance_monitor::kProcessChromeAggregate,
+      performance_monitor::kMetricSharedMemoryUsage);
+  ASSERT_EQ(2u, stats.size());
+  EXPECT_GT(stats[1].value, 0);
+}
+
 #if !defined(OS_WIN)
 // Disabled on Windows due to a bug where Windows will return a normal exit
 // code in the testing environment, even if the process died (this is not the