Bug 727140 - OOM due to zoom of background tabs going to zero. This prevents viewport resizing happening on background tabs which should be a bit faster.

mobile/android/chrome/content/browser.js

@@ -3204,7 +3204,7 @@ var ViewportHandler = {
   },
 
   onResize: function onResize() {
-    Tabs.getInstance().getSelectedTab().updateViewportSize();        
+    BrowserApp.selectedTab.updateViewportSize();
   },
 
   clamp: function(num, min, max) {