Bug 1016138 - Add telemetry probe for master password usage. r=dolske

browser/base/content/browser.js

@@ -1226,6 +1226,21 @@ var gBrowserInit = {
 
       SocialUI.init();
       TabView.init();
+
+      // Telemetry for master-password - we do this after 5 seconds as it
+      // can cause IO if NSS/PSM has not already initialized.
+      setTimeout(() => {
+        if (window.closed) {
+          return;
+        }
+        let secmodDB = Cc["@mozilla.org/security/pkcs11moduledb;1"]
+                       .getService(Ci.nsIPKCS11ModuleDB);
+        let slot = secmodDB.findSlotByName("");
+        let mpEnabled = slot &&
+                        slot.status != Ci.nsIPKCS11Slot.SLOT_UNINITIALIZED &&
+                        slot.status != Ci.nsIPKCS11Slot.SLOT_READY;
+        Services.telemetry.getHistogramById("MASTER_PASSWORD_ENABLED").add(mpEnabled);
+      }, 5000);
     });
     this.delayedStartupFinished = true;
 

toolkit/components/telemetry/Histograms.json

@@ -6418,5 +6418,10 @@
     "kind": "enumerated",
     "n_values": 30,
     "description": "Algorithms used with WebCrypto (see table in WebCryptoTask.cpp)"
+  },
+  "MASTER_PASSWORD_ENABLED": {
+    "expires_in_version": "never",
+    "kind": "flag",
+    "description": "If a master-password is enabled for this profile"
   }
 }