Add BytesRead metric to CPM

chrome/browser/performance_monitor/performance_monitor.h

Index: chrome/browser/performance_monitor/performance_monitor.h
diff --git a/chrome/browser/performance_monitor/performance_monitor.h b/chrome/browser/performance_monitor/performance_monitor.h
index b593ad943657423326db169f803258434d809cc5..d4bc4202ab7772c94a5a2ecd2ae1d894e460260e 100644
--- a/chrome/browser/performance_monitor/performance_monitor.h
+++ b/chrome/browser/performance_monitor/performance_monitor.h
@@ -51,6 +51,10 @@ class PerformanceMonitor : public content::NotificationObserver {
   // start collecting data.
   void Start();
 
+  // Inform PerformanceMonitor that bytes have been read; increment the count
+  // accordingly.
+  void BytesRead(int bytes);
+
   // content::NotificationObserver
   // Wait for various notifications; insert events into the database upon
   // occurance.
@@ -60,6 +64,7 @@ class PerformanceMonitor : public content::NotificationObserver {
 
   Database* database() { return database_.get(); }
   FilePath database_path() { return database_path_; }
+  static bool enabled() { return enabled_; }
 
  private:
   friend struct DefaultSingletonTraits<PerformanceMonitor>;
@@ -68,6 +73,7 @@ class PerformanceMonitor : public content::NotificationObserver {
                            OneProfileUncleanExit);
   FRIEND_TEST_ALL_PREFIXES(PerformanceMonitorUncleanExitBrowserTest,
                            TwoProfileUncleanExit);
+  FRIEND_TEST_ALL_PREFIXES(PerformanceMonitorBrowserTest, BytesRead);
 
   PerformanceMonitor();
   virtual ~PerformanceMonitor();
@@ -138,6 +144,11 @@ class PerformanceMonitor : public content::NotificationObserver {
   void AddCrashEvent(
       const content::RenderProcessHost::RendererClosedDetails& details);
 
+  // A count of how many bytes have been read. This corresponds to the total
+  // number of bytes that have been read since PerformanceMonitor first started

[battre, 2012/08/21 16:16:04]

"have been read from where"? net/disk/...

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

Good point. I found this through TaskManager's code, and didn't think to check
that the Network column would refer to multiple places (but it does). This has
now been separated into two metrics. Thanks :)

+  // recording, and persists across browser runs.
+  int64 bytes_read_;
+
   // The location at which the database files are stored; if empty, the database
   // will default to '<user_data_dir>/performance_monitor_dbs'.
   FilePath database_path_;
@@ -152,6 +163,12 @@ class PerformanceMonitor : public content::NotificationObserver {
 
   content::NotificationRegistrar registrar_;
 
+  // A flag indicating whether or not PerformanceMonitor is enabled. Any
+  // external sources accessing PerformanceMonitor should either wait for
+  // the PERFORMANCE_MONITOR_INITIALIZED notification or should check this
+  // flag.
+  static bool enabled_;

[battre, 2012/08/21 16:16:04]

static attributes don't use the _ notation but use a g_ prefix. See "static int
g_max_queueing_delay_ms = 0;" in predictor.cc. You would move the variable to
the .cc file.

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

Isn't the g_ prefix only for global data?

I think I have seen this pattern before:
http://code.google.com/searchframe#OAMlx_jo-ck/src/base/time.h&exact_package=...
http://code.google.com/searchframe#OAMlx_jo-ck/src/chrome/browser/jankometer....

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

Other examples:
http://code.google.com/searchframe#OAMlx_jo-ck/src/base/metrics/statistics_re...
http://code.google.com/searchframe#OAMlx_jo-ck/src/chrome/browser/browsing_da...
(examples where a static bool is returned in a accessor function)

+
   DISALLOW_COPY_AND_ASSIGN(PerformanceMonitor);
 };