Bug 738194 - Directly use editor.markupDocumentViewer in editingOverlay.js as it now is defined in base toolkit/content/widgets/editor.xml. r=neil

editor/ui/composer/content/editingOverlay.js

@@ -117,8 +117,7 @@ function EditorStartup(aUrl, aCharset)
   // Get url for editor content and load it. The editor gets instantiated by
   // the editingSession when the URL has finished loading.
   try {
-    var contentViewer = GetCurrentEditorElement().docShell.contentViewer;
-    contentViewer.QueryInterface(Components.interfaces.nsIMarkupDocumentViewer);
+    var contentViewer = GetCurrentEditorElement().markupDocumentViewer;
     contentViewer.defaultCharacterSet = aCharset;
     contentViewer.forceCharacterSet = aCharset;
   } catch (e) {}