Add UpdateCurrentAppInfo() interface to record info about current app, including

chromecast/base/metrics/cast_metrics_helper.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMECAST_BASE_METRICS_CAST_METRICS_HELPER_H_
 #define CHROMECAST_BASE_METRICS_CAST_METRICS_HELPER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 13 matching lines @@
 class CastMetricsHelper {
  public:
   enum BufferingType {
     kInitialBuffering,
     kBufferingAfterUnderrun,
     kAbortedBuffering,
   };
 
   typedef base::Callback<void(const std::string&)> RecordActionCallback;
 
+  struct MetricsAppInfo {
+    MetricsAppInfo();
+    ~MetricsAppInfo();

[byungchul, 2014/12/11 00:15:26]

Not necessary

[gfhuang, 2014/12/11 02:59:39]

Done.

+
+    std::string action_name;
+    std::string app_id;
+    std::string session_id;
+    std::string sdk_version;
+  };
+
   class MetricsSink {
    public:
     virtual ~MetricsSink() {}
 
     virtual void OnAction(const std::string& action) = 0;
     virtual void OnEnumerationEvent(const std::string& name,
                                     int value, int num_buckets) = 0;
     virtual void OnTimeEvent(const std::string& name,
                              const base::TimeDelta& value,
                              const base::TimeDelta& min,
                              const base::TimeDelta& max,
                              int num_buckets) = 0;
   };
 
+  // Delimiter character used in GetMetricsNameWithAppInfo().
+  static const char kMetricsNameAppInfoDelimiter;

[gunsch, 2014/12/10 22:43:58]

will this be referenced outside this file? I would hope not, if MetricsAppInfo
is being both serialized/deserialized inside the impementation

[gfhuang, 2014/12/11 02:59:39]

Done.

+
+  // Decodes action_name/app_id/session_id/sdk_version from metrics name
+  // generated from GetMetricsNameWithAppInfo().
+  static MetricsAppInfo GetAppInfoFromMetricsName(
+      const std::string& metrics_name);

[byungchul, 2014/12/11 00:15:26]

Do we prefer structure copy? Why not get out param?

and name should be Get(or Extract)MetricsAppInfoFromMetricsName?

[gfhuang, 2014/12/11 02:59:39]

Done.

[byungchul, 2014/12/11 18:35:49]

Though I meant passing the pointer of the structure, I am fine with this either.
Jesse may have a different opinion.

[gfhuang, 2014/12/11 19:20:26]

Ack. define struct has an extra burden to maintain, i think it's ok since only 4
simple fields.

+
   static CastMetricsHelper* GetInstance();
 
   explicit CastMetricsHelper(
       scoped_refptr<base::MessageLoopProxy> message_loop_proxy);
   virtual ~CastMetricsHelper();
 
   // This function stores the name and startup time of the active application.
   virtual void TagAppStart(const std::string& app_name);
+  // This function updates the info for current active application.
+  virtual void UpdateCurrentAppInfo(const std::string& app_id,
+                                    const std::string& session_id,
+                                    const std::string& sdk_version);
 
   // Logs UMA record for media play/pause user actions.
   virtual void LogMediaPlay();
   virtual void LogMediaPause();
 
   // Logs a simple UMA user action.
   // This is used as an in-place replacement of content::RecordComputedAction().
   virtual void RecordSimpleAction(const std::string& action);
 
   // Logs UMA record of the elapsed time from the app launch
   // to the time first video frame is displayed.
   virtual void LogTimeToDisplayVideo();
 
   // Logs UMA record of the time needed to re-buffer A/V.
   virtual void LogTimeToBufferAv(BufferingType buffering_type,
                                  base::TimeDelta time);
 
   virtual void ResetVideoFrameSampling();
 
   // Logs UMA statistics for video decoder and rendering data.
   // Negative values are considered invalid and will not be logged.
   virtual void LogFramesPer5Seconds(int displayed_frames, int dropped_frames,
                                     int delayed_frames, int error_frames);
 
   // Returns metrics name with app name between prefix and suffix.
   virtual std::string GetMetricsNameWithAppName(
       const std::string& prefix,
       const std::string& suffix) const;
+  // Returns metrics name with app_id/session_id/sdk_version.
+  virtual std::string GetMetricsNameWithAppInfo(
+      const std::string& action_name) const;
 
   // Provides a MetricsSink instance to delegate UMA event logging.
   // Once the delegate interface is set, CastMetricsHelper will not log UMA
   // events internally unless SetMetricsSink(NULL) is called.
   // CastMetricsHelper can only hold one MetricsSink instance.
   // Caller retains ownership of MetricsSink.
   virtual void SetMetricsSink(MetricsSink* delegate);
 
   // Sets a default callback to record user action when MetricsSink is not set.
   // This function could be called multiple times (in unittests), and
@@ skipping 17 matching lines @@
   void LogMediumTimeHistogramEvent(const std::string& name,
                                    const base::TimeDelta& value);
 
   scoped_refptr<base::MessageLoopProxy> message_loop_proxy_;
 
   // Start time of the most recent app.
   base::TimeTicks app_start_time_;
 
   // Currently running app name. Used to construct histogram name.
   std::string app_name_;
+  std::string app_id_;
+  std::string session_id_;
+  std::string sdk_version_;
 
   // Whether a new app start time has been stored but not recorded.
   // After the startup time has been used to generate an UMA event,
   // this is set to false.
   bool new_startup_time_;
 
   base::TimeTicks previous_video_stat_sample_time_;
 
   MetricsSink* metrics_sink_;
   // Default RecordAction callback when metrics_sink_ is not set.
   RecordActionCallback record_action_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CastMetricsHelper);
 };
 
 }  // namespace metrics
 }  // namespace chromecast
 
 #endif  // CHROMECAST_BASE_METRICS_CAST_METRICS_HELPER_H_