Expose metrics to Ghostery extension via extension messaging.

src/api.js

@@ -0,0 +1,14 @@
+/**
+ * API for external communication from Ghostery browser extension
+ */
+
+const ALLOWED_ADDON_IDS = new Set(["firefox@ghostery.com"]);
+
+browser.runtime.onMessageExternal.addListener(async (message, sender) => {
+  if (!ALLOWED_ADDON_IDS.has(sender.id)) {
+    return false;
+  }
+  if (message === "getMetrics") {
+    return getMetrics();
+  }
+});

src/experiment_apis/ghostery_parent.js

@@ -34,6 +34,11 @@ global.ghostery = class extends ExtensionCommon.ExtensionAPI {
           const window = getWindow(windowId);
           window.gURLBar.value = query || '';
           window.gURLBar.focus();
+        },
+        isDefaultBrowser() {
+          const shell = Components.classes["@mozilla.org/browser/shell-service;1"]
+            .getService(Components.interfaces.nsIShellService)
+          return shell.isDefaultBrowser();
         }
       }
     }

src/experiment_apis/ghostery_schema.json

@@ -42,6 +42,16 @@
       "name": "query",
       "optional": true
     }]
+  },
+  {
+    "name": "isDefaultBrowser",
+    "type": "function",
+    "async": true,
+    "description": "Check if this is the OS's default browser",
+    "parameters": [],
+    "returns": {
+      "description": "true if this is the default browser"
+    }
   }
   ],
   "events": [

src/manifest.json

@@ -11,7 +11,9 @@
       "token-pool.js",
       "sjcl.js",
       "background.js",
-      "choice-screen.js"
+      "choice-screen.js",
+      "metrics.js",
+      "api.js"
     ]
   },
   "content_scripts": [{

src/metrics.js

@@ -0,0 +1,45 @@
+// limit engines we can send to the specific set we're interested in from search choice screen
+const searchEngineMap = {
+  "Ghostery Search": "ghostery",
+  Google: "google",
+  Bing: "bing",
+  StartPage: "sp",
+  Yahoo: "yahoo",
+};
+
+async function getMetrics() {
+  return {
+    ds: await getDefaultSearchEngine(),
+    db: await getIsDefaultBrowser(),
+  };
+}
+
+/**
+ * Get the name of the current default search engine (if it is in the searchEngineMap list).
+ * Returns "other" if the engine is not in the shortlist, and empty string if the search API is not
+ * available.
+ */
+async function getDefaultSearchEngine() {
+  if (browser.search) {
+    const engines = await browser.search.get();
+    const defaultSearchEngine = engines.find((s) => s.isDefault).name;
+    return searchEngineMap[defaultSearchEngine] || "other";
+  }
+  return "";
+}
+
+/**
+ * Get default browser state:
+ *  0 = unknown - API to check is missing
+ *  1 = not default browser
+ *  2 = is default browser
+ */
+async function getIsDefaultBrowser() {
+  if (browser.ghostery) {
+    if (await browser.ghostery.isDefaultBrowser()) {
+      return 2;
+    }
+    return 1;
+  }
+  return 0;
+}