Introducing phased profiling framework

chrome/browser/metrics/chrome_metrics_service_client.h

Index: chrome/browser/metrics/chrome_metrics_service_client.h
diff --git a/chrome/browser/metrics/chrome_metrics_service_client.h b/chrome/browser/metrics/chrome_metrics_service_client.h
index 2b95742b3cf670e477beb56ce1e19e3579884cbb..83462b0246cd481c44cb85ecb706d0d3a97df5d7 100644
--- a/chrome/browser/metrics/chrome_metrics_service_client.h
+++ b/chrome/browser/metrics/chrome_metrics_service_client.h
@@ -94,8 +94,13 @@ class ChromeMetricsServiceClient
 
   // TrackingSynchronizerObserver:
   void ReceivedProfilerData(
-      const tracked_objects::ProcessDataSnapshot& process_data,
-      int process_type) override;
+      const tracked_objects::ProcessDataPhaseSnapshot& process_data_phase,
+      base::ProcessId process_id,
+      content::ProcessType process_type,
+      int profiling_phase,
+      const base::TimeDelta& profiling_phase_start,

[dcheng, 2015/03/27 08:36:36]

TimeDelta is typically passed by value:
https://code.google.com/p/chromium/codesearch#chromium/src/base/time/time.h&l=20

+      const base::TimeDelta& profiling_phase_finish,
+      const metrics::ProfilerEvents& past_profiler_events) override;
   void FinishedReceivingProfilerData() override;
 
   // Callbacks for various stages of final log info collection. Do not call