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

app_id, session_id and sdk_version, which are used by MediaPlay/MediaPause
events.

BUG=

Review URL: https://codereview.chromium.org/786233003

Cr-Commit-Position: refs/heads/master@{#308026}

2 files changed, 89 insertions, 2 deletions

diff --git a/chromecast/base/metrics/cast_metrics_helper.cc b/chromecast/base/metrics/cast_metrics_helper.cc
index dda5f51..70bef88 100644
--- a/chromecast/base/metrics/cast_metrics_helper.cc
+++ b/chromecast/base/metrics/cast_metrics_helper.cc
@@ -10,6 +10,8 @@
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/user_metrics.h"
+#include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
 #include "chromecast/base/metrics/cast_histograms.h"
 #include "chromecast/base/metrics/grouped_histogram.h"
 
@@ -36,8 +38,55 @@ const int kDisplayedFramesPerSecondPeriod = 1000000;
 // Sample every 5 seconds, represented in microseconds.
 const int kNominalVideoSamplePeriod = 5000000;
 
+const char kMetricsNameAppInfoDelimiter = '#';
+
 }  // namespace
 
+// static
+
+// NOTE(gfhuang): This is a hacky way to encode/decode app infos into a
+// string. Mainly because it's hard to add another metrics serialization type
+// into components/metrics/serialization/.
+// static
+bool CastMetricsHelper::DecodeAppInfoFromMetricsName(
+    const std::string& metrics_name,
+    std::string* action_name,
+    std::string* app_id,
+    std::string* session_id,
+    std::string* sdk_version) {
+  DCHECK(action_name);
+  DCHECK(app_id);
+  DCHECK(session_id);
+  DCHECK(sdk_version);
+  if (metrics_name.find(kMetricsNameAppInfoDelimiter) == std::string::npos)
+    return false;
+
+  std::vector<std::string> tokens;
+  base::SplitString(metrics_name, kMetricsNameAppInfoDelimiter, &tokens);
+  DCHECK_EQ(tokens.size(), 4u);
+  // The order of tokens should match EncodeAppInfoIntoMetricsName().
+  *action_name = tokens[0];
+  *app_id = tokens[1];
+  *session_id = tokens[2];
+  *sdk_version = tokens[3];
+  return true;
+}
+
+// static
+std::string CastMetricsHelper::EncodeAppInfoIntoMetricsName(
+    const std::string& action_name,
+    const std::string& app_id,
+    const std::string& session_id,
+    const std::string& sdk_version) {
+  std::vector<std::string> parts;
+  parts.push_back(action_name);
+  parts.push_back(app_id);
+  parts.push_back(session_id);
+  parts.push_back(sdk_version);
+  return JoinString(parts, kMetricsNameAppInfoDelimiter);
+}
+
+// static
 CastMetricsHelper* CastMetricsHelper::GetInstance() {
   DCHECK(g_instance);
   return g_instance;
@@ -71,14 +120,29 @@ void CastMetricsHelper::TagAppStart(const std::string& arg_app_name) {
   new_startup_time_ = true;
 
   TagAppStartForGroupedHistograms(app_name_);
+  // Clear app info
+  UpdateCurrentAppInfo("", "", "");
+}
+
+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", ""));
+  MAKE_SURE_THREAD(LogMediaPlay);
+  RecordSimpleAction(EncodeAppInfoIntoMetricsName(
+      "MediaPlay", app_id_, session_id_, sdk_version_));
 }
 
 void CastMetricsHelper::LogMediaPause() {
-  RecordSimpleAction(GetMetricsNameWithAppName("MediaPause", ""));
+  MAKE_SURE_THREAD(LogMediaPause);
+  RecordSimpleAction(EncodeAppInfoIntoMetricsName(
+      "MediaPause", app_id_, session_id_, sdk_version_));
 }
 
 void CastMetricsHelper::LogTimeToDisplayVideo() {
diff --git a/chromecast/base/metrics/cast_metrics_helper.h b/chromecast/base/metrics/cast_metrics_helper.h
index 9bacdcb..fb22ff8 100644
--- a/chromecast/base/metrics/cast_metrics_helper.h
+++ b/chromecast/base/metrics/cast_metrics_helper.h
@@ -45,6 +45,16 @@ class CastMetricsHelper {
                              int num_buckets) = 0;
   };
 
+  // Decodes action_name/app_id/session_id/sdk_version from metrics name.
+  // Return false if the metrics name is not generated from
+  // EncodeAppInfoIntoMetricsName() with correct format.
+  static bool DecodeAppInfoFromMetricsName(
+      const std::string& metrics_name,
+      std::string* action_name,
+      std::string* app_id,
+      std::string* session_id,
+      std::string* sdk_version);
+
   static CastMetricsHelper* GetInstance();
 
   explicit CastMetricsHelper(
@@ -53,6 +63,10 @@ class 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();
@@ -101,6 +115,12 @@ class CastMetricsHelper {
   CastMetricsHelper();
 
  private:
+  static std::string EncodeAppInfoIntoMetricsName(
+      const std::string& action_name,
+      const std::string& app_id,
+      const std::string& session_id,
+      const std::string& sdk_version);
+
   void LogEnumerationHistogramEvent(const std::string& name,
                                     int value, int num_buckets);
   void LogTimeHistogramEvent(const std::string& name,
@@ -118,6 +138,9 @@ class CastMetricsHelper {
 
   // 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,