Bug 1673346 - Don't init FOG if not MOZ_GLEAN r=janerik

Differential Revision: https://phabricator.services.mozilla.com/D94738

browser/components/BrowserGlue.jsm

@@ -2643,10 +2643,12 @@ BrowserGlue.prototype = {
       // pre-init buffer.
       {
         task: () => {
-          let FOG = Cc["@mozilla.org/toolkit/glean;1"].createInstance(
-            Ci.nsIFOG
-          );
-          FOG.initializeFOG();
+          if (AppConstants.MOZ_GLEAN) {
+            let FOG = Cc["@mozilla.org/toolkit/glean;1"].createInstance(
+              Ci.nsIFOG
+            );
+            FOG.initializeFOG();
+          }
         },
       },
 

toolkit/modules/AppConstants.jsm

@@ -419,4 +419,11 @@ this.AppConstants = Object.freeze({
 #else
     true,
 #endif
+
+  MOZ_GLEAN:
+#ifdef MOZ_GLEAN
+    true,
+#else
+    false,
+#endif
 });