--- a/widget/gtk/gtk3drawing.cpp
+++ b/widget/gtk/gtk3drawing.cpp
@@ -37,16 +37,19 @@ moz_gtk_get_tab_thickness(GtkStyleContex
 
 static gint
 moz_gtk_menu_item_paint(WidgetNodeType widget, cairo_t *cr, GdkRectangle* rect,
                         GtkWidgetState* state, GtkTextDirection direction);
 
 static GtkBorder
 GetMarginBorderPadding(GtkStyleContext* aStyle);
 
+static void
+InsetByMargin(GdkRectangle* rect, GtkStyleContext* style);
+
 // GetStateFlagsFromGtkWidgetState() can be safely used for the specific
 // GtkWidgets that set both prelight and active flags.  For other widgets,
 // either the GtkStateFlags or Gecko's GtkWidgetState need to be carefully
 // adjusted to match GTK behavior.  Although GTK sets insensitive and focus
 // flags in the generic GtkWidget base class, GTK adds prelight and active
 // flags only to widgets that are expected to demonstrate prelight or active
 // states.  This contrasts with HTML where any element may have :active and
 // :hover states, and so Gecko's GtkStateFlags do not necessarily map to GTK
@@ -297,16 +300,26 @@ moz_gtk_button_paint(cairo_t *cr, GdkRec
         height -= (border.top + border.bottom);
         gtk_render_focus(style, cr, x, y, width, height);
     }
     gtk_style_context_restore(style);
     return MOZ_GTK_SUCCESS;
 }
 
 static gint
+moz_gtk_header_bar_button_paint(cairo_t *cr, GdkRectangle* rect,
+                                GtkWidgetState* state,
+                                GtkReliefStyle relief, GtkWidget* widget,
+                                GtkTextDirection direction)
+{
+    InsetByMargin(rect, gtk_widget_get_style_context(widget));
+    return moz_gtk_button_paint(cr, rect, state, relief, widget, direction);
+}
+
+static gint
 moz_gtk_toggle_paint(cairo_t *cr, GdkRectangle* rect,
                      GtkWidgetState* state,
                      gboolean selected, gboolean inconsistent,
                      gboolean isradio, GtkTextDirection direction)
 {
     GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
     gint indicator_size, indicator_spacing;
     gint x, y, width, height;
@@ -1943,16 +1956,31 @@ moz_gtk_info_bar_paint(cairo_t *cr, GdkR
                         GetStateFlagsFromGtkWidgetState(state));
     gtk_render_background(style, cr, rect->x, rect->y, rect->width,
                           rect->height);
     gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
 
     return MOZ_GTK_SUCCESS;
 }
 
+static gint
+moz_gtk_header_bar_paint(WidgetNodeType widgetType,
+                         cairo_t *cr, GdkRectangle* rect, GtkWidgetState* state)
+{
+    GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+    GtkStyleContext *style = GetStyleContext(widgetType, GTK_TEXT_DIR_LTR,
+                                             state_flags);
+    InsetByMargin(rect, style);
+    gtk_render_background(style, cr, rect->x, rect->y, rect->width,
+                          rect->height);
+    gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+    return MOZ_GTK_SUCCESS;
+}
+
 static void
 moz_gtk_add_style_margin(GtkStyleContext* style,
                          gint* left, gint* top, gint* right, gint* bottom)
 {
     GtkBorder margin;
 
     gtk_style_context_get_margin(style, GTK_STATE_FLAG_NORMAL, &margin);
 
@@ -2205,16 +2233,32 @@ moz_gtk_get_widget_border(WidgetNodeType
                                               left, top, right, bottom);
 
             GtkStyleContext* labelStyle = GetStyleContext(MOZ_GTK_TOOLTIP_BOX_LABEL);
             moz_gtk_add_margin_border_padding(labelStyle,
                                               left, top, right, bottom);
 
             return MOZ_GTK_SUCCESS;
         }
+    case MOZ_GTK_HEADER_BAR:
+    case MOZ_GTK_HEADER_BAR_MAXIMIZED:
+        {
+            style = GetStyleContext(widget);
+            moz_gtk_add_style_border(style, left, top, right, bottom);
+            moz_gtk_add_style_padding(style, left, top, right, bottom);
+            return MOZ_GTK_SUCCESS;
+        }
+    case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+        {
+            style = GetStyleContext(widget);
+            moz_gtk_add_margin_border_padding(style, left, top, right, bottom);
+            return MOZ_GTK_SUCCESS;
+        }
 
     /* These widgets have no borders, since they are not containers. */
     case MOZ_GTK_CHECKBUTTON_LABEL:
     case MOZ_GTK_RADIOBUTTON_LABEL:
     case MOZ_GTK_SPLITTER_HORIZONTAL:
     case MOZ_GTK_SPLITTER_VERTICAL:
     case MOZ_GTK_CHECKBUTTON:
     case MOZ_GTK_RADIOBUTTON:
@@ -2666,16 +2710,24 @@ moz_gtk_widget_paint(WidgetNodeType widg
                                         GetWidget(MOZ_GTK_TOGGLE_BUTTON),
                                         direction);
         }
         return moz_gtk_button_paint(cr, rect, state,
                                     (GtkReliefStyle) flags,
                                     GetWidget(MOZ_GTK_BUTTON),
                                     direction);
         break;
+    case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+        return moz_gtk_header_bar_button_paint(cr, rect, state,
+                                               (GtkReliefStyle) flags,
+                                               GetWidget(widget),
+                                               direction);
+        break;
     case MOZ_GTK_CHECKBUTTON:
     case MOZ_GTK_RADIOBUTTON:
         return moz_gtk_toggle_paint(cr, rect, state,
                                     !!(flags & MOZ_GTK_WIDGET_CHECKED),
                                     !!(flags & MOZ_GTK_WIDGET_INCONSISTENT),
                                     (widget == MOZ_GTK_RADIOBUTTON),
                                     direction);
         break;
@@ -2872,16 +2924,20 @@ moz_gtk_widget_paint(WidgetNodeType widg
         return moz_gtk_hpaned_paint(cr, rect, state);
         break;
     case MOZ_GTK_WINDOW:
         return moz_gtk_window_paint(cr, rect, direction);
         break;
     case MOZ_GTK_INFO_BAR:
         return moz_gtk_info_bar_paint(cr, rect, state);
         break;
+    case MOZ_GTK_HEADER_BAR:
+    case MOZ_GTK_HEADER_BAR_MAXIMIZED:
+        return moz_gtk_header_bar_paint(widget, cr, rect, state);
+        break;
     default:
         g_warning("Unknown widget type: %d", widget);
     }
 
     return MOZ_GTK_UNKNOWN_WIDGET;
 }
 
 gint