implement tabpanels. not part of the build.

gfx/src/gtk/gtkdrawing.c

@@ -430,3 +430,13 @@ moz_gtk_tab_paint(GdkWindow* window, GtkStyle* style, GdkRectangle* rect,
                         cliprect, gTabWidget, "tab", rect->x - rect->width,
                         rect->y, rect->width, rect->height, GTK_POS_BOTTOM);
 }
+
+void
+moz_gtk_tabpanels_paint(GdkWindow* window, GtkStyle* style,
+                        GdkRectangle* rect, GdkRectangle* cliprect)
+{
+  gtk_paint_box(style, window, GTK_STATE_NORMAL, GTK_SHADOW_OUT,
+                cliprect, gTabWidget, "notebook", rect->x, rect->y,
+                rect->width, rect->height);
+}
+

gfx/src/gtk/gtkdrawing.h

@@ -134,6 +134,10 @@ void
 moz_gtk_tab_paint(GdkWindow* window, GtkStyle* style, GdkRectangle* rect,
                   GdkRectangle* cliprect, GtkTabType type);
 
+void
+moz_gtk_tabpanels_paint(GdkWindow* window, GtkStyle* style,
+                        GdkRectangle* rect, GdkRectangle* cliprect);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */

gfx/src/gtk/nsNativeThemeGTK.cpp

@@ -354,9 +354,10 @@ nsNativeThemeGTK::DrawWidgetBackground(nsIRenderingContext* aContext,
                                  &gdk_clip);
     break;
 
-//  case NS_THEME_TAB_PANELS:
-//    EnsureTabWidget();
-//    break;
+  case NS_THEME_TAB_PANELS:
+    EnsureTabWidget();
+    moz_gtk_tabpanels_paint(window, gTabWidget->style, &gdk_rect, &gdk_clip);
+    break;
 
   case NS_THEME_TAB:
   case NS_THEME_TAB_LEFT_EDGE:
@@ -442,6 +443,10 @@ nsNativeThemeGTK::GetWidgetBorder(nsIDeviceContext* aContext, nsIFrame* aFrame,
     EnsureProgressBarWidget();
     WidgetBorderToMargin(gProgressWidget, aResult);
     break;
+  case NS_THEME_TAB_PANELS:
+    EnsureTabWidget();
+    WidgetBorderToMargin(gTabWidget, aResult);
+    break;
   }
 
   return NS_OK;
@@ -605,7 +610,7 @@ nsNativeThemeGTK::ThemeSupportsWidget(nsIPresContext* aPresContext,
     // case NS_THEME_TAB_PANEL:
     case NS_THEME_TAB_LEFT_EDGE:
     case NS_THEME_TAB_RIGHT_EDGE:
-    // case NS_THEME_TAB_PANELS:
+    case NS_THEME_TAB_PANELS:
   case NS_THEME_TOOLTIP:
     // case NS_THEME_SPINNER:
     // case NS_THEME_SPINNER_UP_BUTTON: