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 35 matching lines @@
   };
 
   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 update the info of current active application.

[gunsch, 2014/12/10 16:54:18]

Remove "This function"

"update" --> "Updates"

"of" --> "for"

[gfhuang, 2014/12/10 22:02:41]

Done.

+  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.
+  // This is used by histograms.
   virtual std::string GetMetricsNameWithAppName(
       const std::string& prefix,
       const std::string& suffix) const;
+  // Returns metrics name with app_id/session_id/sdk_version.
+  // This is used by actions, so far MediaPlay/MediaPause only.

[gunsch, 2014/12/10 16:54:19]

This comment is bound to become obsolete. Can you remove the reference to
MediaPlay/MediaPause?

Also, are "used by actions" and "used by histograms" restrictions? If so, can
you encode them into the method names? If not, then you should remove the
comments.

[gfhuang, 2014/12/10 22:02:41]

Done.

+  virtual std::string GetMetricsNameWithAppInfo(

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

does anyone call this externally? seems to me like it should be a private method

+      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 default_record_action_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CastMetricsHelper);
 };
 
 }  // namespace metrics
 }  // namespace chromecast
 
 #endif  // CHROMECAST_BASE_METRICS_CAST_METRICS_HELPER_H_