Bug 763016 - Report telemetry data for if the MozillaMaintenance service is installed. r=rstrong

toolkit/components/telemetry/TelemetryHistograms.h

@@ -318,6 +318,7 @@ HISTOGRAM_BOOLEAN(UPDATER_UPDATES_ENABLED, "Updater: Whether or not updates are
 HISTOGRAM_BOOLEAN(UPDATER_UPDATES_AUTOMATIC, "Updater: Whether or not updates are automatic")
 HISTOGRAM_BOOLEAN(UPDATER_SERVICE_ENABLED, "Updater: Whether or not the MozillaMaintenance service is enabled")
 HISTOGRAM(UPDATER_SERVICE_ERRORS, 1, 30, 31, LINEAR, "Updater: The number of MozillaMaintenance service errors that have occurred")
+HISTOGRAM_BOOLEAN(UPDATER_SERVICE_INSTALLED, "Updater: Whether or not the MozillaMaintenance service is installed")
 
 /**
  * Thunderbird-specific telemetry.

toolkit/mozapps/update/nsUpdateService.js

@@ -1609,6 +1609,7 @@ UpdateService.prototype = {
                                       "UPDATER_SERVICE_ENABLED");
       this._sendIntPrefTelemetryPing(PREF_APP_UPDATE_SERVICE_ERRORS,
                                      "UPDATER_SERVICE_ERRORS");
+      this._sendServiceInstalledTelemetryPing();
 #endif
 
       update.statusText = gUpdateBundle.GetStringFromName("installSuccess");
@@ -1666,6 +1667,33 @@ UpdateService.prototype = {
     }
   },
 
+#ifdef XP_WIN
+  /**
+   * Submit a telemetry ping with a boolean value which indicates if the service
+   * is installed.
+   */
+  _sendServiceInstalledTelemetryPing: function AUS__svcInstallTelemetryPing() {
+    let installed = 0;
+    try {
+      let wrk = Components.classes["@mozilla.org/windows-registry-key;1"]
+                .createInstance(Components.interfaces.nsIWindowsRegKey);
+      wrk.open(wrk.ROOT_KEY_LOCAL_MACHINE,
+               "SOFTWARE\\Mozilla\\MaintenanceService",
+               wrk.ACCESS_READ | wrk.WOW64_64);
+      installed = wrk.readIntValue("Installed");
+      wrk.close();
+    } catch(e) {
+    }
+    try {
+      let h = Services.telemetry.getHistogramById("UPDATER_SERVICE_INSTALLED");
+      h.add(installed);
+    } catch(e) {
+      // Don't allow any exception to be propagated.
+      Components.utils.reportError(e);
+    }
+  },
+#endif
+
   /**
    * Submit a telemetry ping with the int value of a pref for a histogram
    *