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 28227107830e6215be58cb763456962a3172550b..91f07a2af795338e90636cb8b461ccd001e6a72e 100644
--- a/chrome/browser/metrics/perf_provider_chromeos.h
+++ b/chrome/browser/metrics/perf_provider_chromeos.h
@@ -12,7 +12,7 @@
 #include "base/threading/non_thread_safe.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
-#include "components/metrics/proto/perf_data.pb.h"
+#include "components/metrics/proto/sampled_profile.pb.h"
 
 namespace metrics {
 
@@ -28,12 +28,13 @@ 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);
 
  private:
   // 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.
+  void ScheduleCollection();
 
   // Collects perf data if it has not been consumed by calling GetPerfData()
   // (see above).
@@ -50,8 +51,8 @@ class PerfProvider : public base::NonThreadSafe {
       scoped_ptr<WindowedIncognitoObserver> incognito_observer,
       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_;
@@ -59,6 +60,9 @@ class PerfProvider : public base::NonThreadSafe {
   // To pass around the "this" pointer across threads safely.
   base::WeakPtrFactory<PerfProvider> weak_factory_;
 
+  // Record of the last login time.
+  base::Time login_time_;

[Ilya Sherman, 2014/05/16 21:48:57]

Did you mean TimeTicks?

[Simon Que, 2014/05/17 03:25:07]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(PerfProvider);
 };