Add BytesRead metric to CPM

chrome/browser/performance_monitor/performance_monitor.cc

Index: chrome/browser/performance_monitor/performance_monitor.cc
diff --git a/chrome/browser/performance_monitor/performance_monitor.cc b/chrome/browser/performance_monitor/performance_monitor.cc
index 38f7192ca207bead318ace9cd48800521db71a54..57db0abaedb2d3acc62ce550f376ed1f09aee12a 100644
--- a/chrome/browser/performance_monitor/performance_monitor.cc
+++ b/chrome/browser/performance_monitor/performance_monitor.cc
@@ -61,7 +61,10 @@ bool StringToTime(std::string time, base::Time* output) {
 
 namespace performance_monitor {
 
-PerformanceMonitor::PerformanceMonitor() : database_(NULL) {
+bool PerformanceMonitor::enabled_ = false;
+
+PerformanceMonitor::PerformanceMonitor() : bytes_read_(0),
+                                           database_(NULL) {
 }
 
 PerformanceMonitor::~PerformanceMonitor() {
@@ -94,6 +97,12 @@ void PerformanceMonitor::Start() {
 void PerformanceMonitor::InitOnBackgroundThread() {
   CHECK(!BrowserThread::CurrentlyOn(BrowserThread::UI));
   database_ = Database::Create(database_path_);
+
+  // Initialize bytes_read_ to the value in the database; if there isn't a
+  // recording in the database, bytes_read_ stays at 0.
+  MetricInfo info;
+  if (database_->GetRecentStatsForActivityAndMetric(METRIC_BYTES_READ, &info))
+    bytes_read_ = info.value;
 }
 
 void PerformanceMonitor::FinishInit() {
@@ -244,11 +253,15 @@ void PerformanceMonitor::NotifyInitialized() {
       chrome::NOTIFICATION_PERFORMANCE_MONITOR_INITIALIZED,
       content::Source<PerformanceMonitor>(this),
       content::NotificationService::NoDetails());
+
+  enabled_ = true;

[Yoyo Zhou, 2012/08/18 01:48:56]

It might be a little misleading to have this be set late in the startup, and yet
be called 'enabled', which seems like a property set at browser startup.

[Devlin, 2012/08/21 19:46:46]

Done.

 }
 
 void PerformanceMonitor::GatherStatisticsOnBackgroundThread() {
   CHECK(!BrowserThread::CurrentlyOn(BrowserThread::UI));
 
+  database_->AddMetric(METRIC_BYTES_READ, base::Int64ToString(bytes_read_));
+
   // Because the CPU usage is gathered as an average since the last time the
   // function was called, while the memory usage is gathered as an instantaneous
   // usage, the CPU usage is gathered before the metrics map is wiped.
@@ -362,6 +375,16 @@ void PerformanceMonitor::UpdateLiveProfilesHelper(
 
 void PerformanceMonitor::DoTimedCollections() {
   UpdateLiveProfiles();
+
+  BrowserThread::PostBlockingPoolSequencedTask(
+      Database::kDatabaseSequenceToken,
+      FROM_HERE,
+      base::Bind(&PerformanceMonitor::GatherStatisticsOnBackgroundThread,
+                 base::Unretained(this)));
+}
+
+void PerformanceMonitor::BytesRead(int bytes_read) {

[eaugusti, 2012/08/21 17:17:26]

IO thread only?

[Devlin, 2012/08/21 19:46:46]

Done.

+  bytes_read_ += bytes_read;
 }
 
 void PerformanceMonitor::Observe(int type,