metrics: Use absolute interval-based perf collection

chrome/browser/metrics/perf_provider_chromeos.h

Index: chrome/browser/metrics/perf_provider_chromeos.h
diff --git a/chrome/browser/metrics/perf_provider_chromeos.h b/chrome/browser/metrics/perf_provider_chromeos.h
index 3bd0f467867821098f57d46ec3db82f149def38d..3f458e8bea34471263ebb05c103a26e7c7fb3ed2 100644
--- a/chrome/browser/metrics/perf_provider_chromeos.h
+++ b/chrome/browser/metrics/perf_provider_chromeos.h
@@ -13,7 +13,7 @@
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "chromeos/login/login_state.h"
-#include "components/metrics/proto/perf_data.pb.h"
+#include "components/metrics/proto/sampled_profile.pb.h"
 
 namespace metrics {
 
@@ -29,7 +29,7 @@ class PerfProvider : public base::NonThreadSafe {
 
   // Writes collected perf data protobufs to |perf_data|. Clears all the stored
   // perf data. Returns true if it wrote to |perf_data|.
-  bool GetPerfData(std::vector<PerfDataProto>* perf_data);
+  bool GetPerfData(std::vector<SampledProfile>* perf_data);

[Ilya Sherman, 2014/05/29 22:56:49]

Optional nit: Perhaps name this "GetSampledProfile()", and name the variable
"sampled_profile"?

[Simon Que, 2014/05/30 01:21:45]

Done.

 
  private:
   // Class that listens for changes to the login state. When a normal user logs
@@ -57,26 +57,29 @@ class PerfProvider : public base::NonThreadSafe {
   void Deactivate();
 
   // Starts an internal timer to start collecting perf data. The timer is set to
-  // trigger |interval| after this function call.
-  void ScheduleCollection(const base::TimeDelta& interval);
+  // trigger at a random point in either the current or the next profiling
+  // interval.

[Ilya Sherman, 2014/05/29 22:56:49]

nit: Please update this comment.

[Simon Que, 2014/05/30 01:21:45]

Done.

+  void ScheduleCollection();
 
   // Collects perf data if it has not been consumed by calling GetPerfData()
   // (see above).
-  void CollectIfNecessary();
+  void CollectIfNecessary(SampledProfile::TriggerEvent trigger_event);

[Ilya Sherman, 2014/05/29 22:56:49]

nit: Please update the docs.

[Simon Que, 2014/05/30 01:21:45]

Done.

 
-  // Collects perf data by calling CollectIfNecessary() and reschedules it to be
-  // collected again.
-  void CollectIfNecessaryAndReschedule();
+  // Collects perf data on a repeating basis by calling CollectIfNecessary() and
+  // reschedules it to be collected again.
+  void DoPeriodicCollection();
 
-  // Parses a protobuf from the |data| passed in only if the
+  // Parses a perf data protobuf from the |data| passed in only if the
   // |incognito_observer| indicates that no incognito window had been opened
   // during the profile collection period.
+  // |trigger_event| is the cause of the perf data collection.
   void ParseProtoIfValid(
       scoped_ptr<WindowedIncognitoObserver> incognito_observer,
+      SampledProfile::TriggerEvent trigger_event,
       const std::vector<uint8>& data);
 
-  // Vector of perf data protobufs.
-  std::vector<PerfDataProto> cached_perf_data_;
+  // Vector of SampledProfile protobufs containing perf profiles.
+  std::vector<SampledProfile> cached_perf_data_;
 
   // For scheduling collection of perf data.
   base::OneShotTimer<PerfProvider> timer_;
@@ -84,6 +87,12 @@ class PerfProvider : public base::NonThreadSafe {
   // For detecting when changes to the login state.
   LoginObserver login_observer_;
 
+  // Record of the last login time.
+  base::TimeTicks login_time_;
+
+  // Record of the start of the upcoming profiling interval.
+  base::TimeTicks next_profiling_interval_start_;
+
   // To pass around the "this" pointer across threads safely.
   base::WeakPtrFactory<PerfProvider> weak_factory_;