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

chromecast/base/metrics/cast_metrics_helper.cc

Index: chromecast/base/metrics/cast_metrics_helper.cc
diff --git a/chromecast/base/metrics/cast_metrics_helper.cc b/chromecast/base/metrics/cast_metrics_helper.cc
index 4cf26f194d3533952d03e1808d0f50391b11faf5..12aba55f4719c62ac1ca4b3ea59cb78daeef49f0 100644
--- a/chromecast/base/metrics/cast_metrics_helper.cc
+++ b/chromecast/base/metrics/cast_metrics_helper.cc
@@ -68,14 +68,27 @@ void CastMetricsHelper::TagAppStart(const std::string& arg_app_name) {
   app_name_ = arg_app_name;
   app_start_time_ = base::TimeTicks::Now();
   new_startup_time_ = true;
+  // Clear app info
+  app_id_ = "";

[byungchul, 2014/12/10 05:39:41]

app_id_.clear();

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

Alternately, you could use UpdateCurrentAppInfo("", "", "") --- this would
prevent the two from accidentally getting out of sync in the future, since any
API change would be forced to be updated

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

Done.

+  session_id_ = "";

[byungchul, 2014/12/10 05:39:41]

ditto

+  sdk_version_ = "";

[byungchul, 2014/12/10 05:39:40]

ditto

+}
+
+void CastMetricsHelper::UpdateCurrentAppInfo(const std::string& app_id,
+                                             const std::string& session_id,
+                                             const std::string& sdk_version) {
+  MAKE_SURE_THREAD(UpdateCurrentAppInfo, app_id, session_id, sdk_version);
+  app_id_ = app_id;
+  session_id_ = session_id;
+  sdk_version_ = sdk_version;
 }
 
 void CastMetricsHelper::LogMediaPlay() {
-  RecordSimpleAction(GetMetricsNameWithAppName("MediaPlay", ""));
+  RecordSimpleAction(GetMetricsNameWithAppInfo("MediaPlay"));
 }
 
 void CastMetricsHelper::LogMediaPause() {
-  RecordSimpleAction(GetMetricsNameWithAppName("MediaPause", ""));
+  RecordSimpleAction(GetMetricsNameWithAppInfo("MediaPause"));
 }
 
 void CastMetricsHelper::LogTimeToDisplayVideo() {
@@ -186,6 +199,12 @@ std::string CastMetricsHelper::GetMetricsNameWithAppName(
   return metrics_name;
 }
 
+std::string CastMetricsHelper::GetMetricsNameWithAppInfo(
+    const std::string& action_name) const {
+  DCHECK(message_loop_proxy_->BelongsToCurrentThread());
+  return action_name + "#" + app_id_ + "#" + session_id_ + "#" + sdk_version_;

[byungchul, 2014/12/10 05:39:40]

Please define a constant for delimiter, '#' for somewhere to parse it.

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

Aside: I saw that you're parsing this in a different location in an internal CL.
Why not have the logic for both ways (serializing and deserializing) in this
class, and pass in/return a struct with all three args? Then this awkward
behavior is at least self-contained.

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

Done.

+}
+
 void CastMetricsHelper::SetMetricsSink(MetricsSink* delegate) {
   MAKE_SURE_THREAD(SetMetricsSink, delegate);
   metrics_sink_ = delegate;