Bug 1447705 - Make BackgroundPageThumbs._destroy actually called. Fix leak from BackgroundPageThumbs.jsm. r=kmag.

--HG--
extra : rebase_source : 6b49b19c6ad8ce3dcec09f0a1456480a598b43ec

toolkit/components/thumbnails/BackgroundPageThumbs.jsm

@@ -217,12 +217,15 @@ const BackgroundPageThumbs = {
   },
 
   _init() {
+    Services.prefs.addObserver(ABOUT_NEWTAB_SEGREGATION_PREF, this);
     Services.obs.addObserver(this, "profile-before-change");
   },
 
   observe(subject, topic, data) {
     if (topic == "profile-before-change") {
       this._destroy();
+    } else if (topic == "nsPref:changed" && data == ABOUT_NEWTAB_SEGREGATION_PREF) {
+      BackgroundPageThumbs.renewThumbnailBrowser();
     }
   },
 
@@ -368,13 +371,7 @@ const BackgroundPageThumbs = {
   _destroyBrowserTimeout: DESTROY_BROWSER_TIMEOUT,
 };
 
-Services.prefs.addObserver(ABOUT_NEWTAB_SEGREGATION_PREF,
+BackgroundPageThumbs._init();
-  function(aSubject, aTopic, aData) {
-    if (aTopic == "nsPref:changed" && aData == ABOUT_NEWTAB_SEGREGATION_PREF) {
-      BackgroundPageThumbs.renewThumbnailBrowser();
-    }
-  });
-
 Object.defineProperty(this, "BackgroundPageThumbs", {
   value: BackgroundPageThumbs,
   enumerable: true,