utils:trace: don't require a metawindow

utils.js

@@ -347,9 +347,22 @@ var tweener = {
     }
 };
 
+function isMetaWindow(obj) {
+    return obj && obj.window_type && obj.get_compositor_private;
+}
 
 function trace(topic, ...args) {
-    windowTrace(topic, ...args);
+    if (!topic.match(/.*/)) {
+        return;
+    }
+
+    if (isMetaWindow(args[0])) {
+        windowTrace(topic, ...args);
+    } else {
+        let trace = shortTrace(1).join(" < ");
+        let extraInfo = args.length > 0 ? "\n\t" + args.map(x => x.toString()).join("\n\t") : ""
+        log(topic, trace, extraInfo);
+    }
 }
 
 let existingWindows = new Set();
@@ -359,10 +372,6 @@ function windowTrace(topic, metaWindow, ...rest) {
         return;
     }
 
-    if (!topic.match(/.*/)) {
-        return;
-    }
-
     log(topic, infoMetaWindow(metaWindow).join("\n"), ...rest.join("\n"));
 }