Resizer widget should only use moz-appearance styling in the classic theme.

Icon for modern by Grey Hodge <jesus_x@mozillanews.org>, other changes by Tim
Hill <tim@prismelite.com>, r=jag, sr=bzbarsky

suite/themes/modern/global/global.css

@@ -161,6 +161,13 @@ statusbarpanel {
   margin: 0px !important;
 }
 
+resizer[dir="bottomright"] {
+  background-image: url("chrome://global/skin/icons/resizer.png");
+  cursor: se-resize;
+  width: 15px;
+  height: 15px;
+}
+
 /* ::::: miscellaneous ::::: */
 
 .toolbar-focustarget {

suite/themes/modern/jar.mn

@@ -204,6 +204,7 @@ modern.jar:
   skin/modern/global/icons/tab-new-hov.gif                         (global/icons/tab-new-hov.gif)
   skin/modern/global/icons/tab-new-act.gif                         (global/icons/tab-new-act.gif)
   skin/modern/global/icons/closebox.gif                            (global/icons/closebox.gif)
+  skin/modern/global/icons/resizer.png                             (global/icons/resizer.png)
   skin/modern/global/menu/menu-arrow-dis.gif                       (global/menu/menu-arrow-dis.gif)
   skin/modern/global/menu/menu-arrow-hov.gif                       (global/menu/menu-arrow-hov.gif)
   skin/modern/global/menu/menu-arrow.gif                           (global/menu/menu-arrow.gif)