Bug 828703 - Correct removal of idle-daily observer; r=rnewman

services/healthreport/healthreporter.jsm

@@ -357,9 +357,11 @@ HealthReporter.prototype = Object.freeze({
     // could occur.
     this._shutdownInitiated = true;
 
-    if (this._initialized) {
+    // We may not have registered the observer yet. If not, this will
+    // throw.
+    try {
       Services.obs.removeObserver(this, "idle-daily");
-    }
+    } catch (ex) { }
 
     // If we have collectors, we need to shut down providers.
     if (this._collector) {