Introducing phased profiling framework

components/metrics/profiler/tracking_synchronizer.h

Index: components/metrics/profiler/tracking_synchronizer.h
diff --git a/components/metrics/profiler/tracking_synchronizer.h b/components/metrics/profiler/tracking_synchronizer.h
index fefe8d9457eb7c9e91798261f890cf3b7c9590d6..c7e87e3a2a025bb7c5d80d7cb7ac5195a2209283 100644
--- a/components/metrics/profiler/tracking_synchronizer.h
+++ b/components/metrics/profiler/tracking_synchronizer.h
@@ -13,6 +13,8 @@
 #include "base/lazy_instance.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "components/metrics/proto/chrome_user_metrics_extension.pb.h"
 #include "content/public/browser/profiler_subscriber.h"
 
 // This class maintains state that is used to upload profiler data from the
@@ -42,7 +44,7 @@ class TrackingSynchronizer
   // used to communicate between the IO and UI thread, and is destroyed only as
   // the main thread (browser_main) terminates, which means the IO thread has
   // already completed, and will not need this instance any further.
-  TrackingSynchronizer();
+  TrackingSynchronizer(const base::TimeTicks& current_time);

[Ilya Sherman, 2015/03/14 00:20:35]

nit: explicit

[vadimt, 2015/03/14 01:39:15]

Done.

 
   // Contact all processes, and get them to upload to the browser any/all
   // changes to profiler data. It calls |callback_object|'s SetData method with
@@ -63,6 +65,7 @@ class TrackingSynchronizer
 
  private:
   friend class base::RefCountedThreadSafe<TrackingSynchronizer>;
+  friend class TrackingSynchronizerTest_ProfilerData_Test;

[Ilya Sherman, 2015/03/14 00:20:35]

Please use protected methods rather than friending test code.  The advantage is
that the test API is clearer -- a friend can muck about with arbitrary private
state.

[vadimt, 2015/03/14 01:39:15]

Promising to do in the next CL.
The code is not complete, and I'd have to move some fields in the protected
section just for tests, and then not forget to move them back after a protected
methods that work with these fields are added.
BTW, I have a list of TODO items, wo, won't forget :)

 
   class RequestContext;
 
@@ -75,7 +78,7 @@ class TrackingSynchronizer
   void OnProfilerDataCollected(
       int sequence_number,
       const tracked_objects::ProcessDataSnapshot& profiler_data,
-      int process_type) override;
+      content::ProcessType process_type) override;
 
   // Establish a new sequence_number_, and use it to notify all the processes of
   // the need to supply, to the browser, their tracking data. It also registers
@@ -84,6 +87,13 @@ class TrackingSynchronizer
   int RegisterAndNotifyAllProcesses(
       const base::WeakPtr<TrackingSynchronizerObserver>& callback_object);
 
+  // Notify |observer| about |profiler_data| received from process of type
+  // |process_type|.
+  void SendData(const tracked_objects::ProcessDataSnapshot& profiler_data,
+                content::ProcessType process_type,
+                const base::TimeTicks& current_time,
+                TrackingSynchronizerObserver* observer) const;
+
   // It finds the RequestContext for the given |sequence_number| and notifies
   // the RequestContext's |callback_object_| about the |value|. This is called
   // whenever we receive profiler data from processes. It also records that we
@@ -94,7 +104,7 @@ class TrackingSynchronizer
   void DecrementPendingProcessesAndSendData(
       int sequence_number,
       const tracked_objects::ProcessDataSnapshot& profiler_data,
-      int process_type);
+      content::ProcessType process_type);
 
   // Get a new sequence number to be sent to processes from browser process.
   // This method is accessible on UI thread.
@@ -109,6 +119,19 @@ class TrackingSynchronizer
   // reuse for a long time).
   int last_used_sequence_number_;
 
+  // Sequence of events associated with already completed profiling phases. The
+  // index in the vector is the phase number. The current phase is not included.
+  std::vector<ProfilerEventProto::ProfilerEvent>
+      phase_completion_events_sequence_;
+
+  // Time of the profiling start. Used to calculate times of phase change
+  // moments relative to this value.
+  const base::TimeTicks start_time_;
+
+  // Times of starts of all profiling phases, including the current phase. The
+  // index in the vector is the phase number.
+  std::vector<base::TimeTicks> phase_start_times_;
+
   DISALLOW_COPY_AND_ASSIGN(TrackingSynchronizer);
 };