Bug 1550893 - Fix the implicit builtinclassness for some Windows widg…

…et interfaces. r=bobowen

nsITaskbarTabPreview has a notxpcom method, so it has always been
treated as builtinclass. This just makes it explicit.

The same thing is true for nsIPrintSettingsWin, but as far as I can
tell it is never actually used from JS, so I just removed the
scriptable tag.

Differential Revision: https://phabricator.services.mozilla.com/D30981

--HG--
extra : moz-landing-system : lando

widget/nsIPrintSettingsWin.idl

@@ -18,7 +18,7 @@
 /**
  * Simplified PrintSettings for Windows interface
  */
-[scriptable, uuid(c63eed41-6ac5-459e-8a64-033eb9ad770a)]
+[uuid(c63eed41-6ac5-459e-8a64-033eb9ad770a)]
 interface nsIPrintSettingsWin : nsISupports
 {
   /**

widget/nsITaskbarTabPreview.idl

@@ -20,7 +20,7 @@ interface imgIContainer;
  * An application may have as many tab previews per window as memory allows.
  *
  */
-[scriptable, uuid(11E4C8BD-5C2D-4E1A-A9A1-79DD5B0FE544)]
+[scriptable, builtinclass, uuid(11E4C8BD-5C2D-4E1A-A9A1-79DD5B0FE544)]
 interface nsITaskbarTabPreview : nsITaskbarPreview
 {
   /**