Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2179 insertions, 0 deletions

diff --git a/widget/gtk/gtk3drawing.cpp b/widget/gtk/gtk3drawing.cpp
new file mode 100644
index 0000000000..1fa8b95606
--- /dev/null
+++ b/widget/gtk/gtk3drawing.cpp
@@ -0,0 +1,2179 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This file contains painting functions for each of the gtk2 widgets.
+ * Adapted from the gtkdrawing.c, and gtk+2.0 source.
+ */
+
+#include <gtk/gtk.h>
+#include <gdk/gdkprivate.h>
+#include <string.h>
+#include "gtkdrawing.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/ScopeExit.h"
+#include "prinrval.h"
+#include "WidgetStyleCache.h"
+#include "nsString.h"
+#include "nsDebug.h"
+#include "WidgetUtilsGtk.h"
+
+#include <math.h>
+#include <dlfcn.h>
+
+static gboolean checkbox_check_state;
+static gboolean notebook_has_tab_gap;
+
+static ToggleGTKMetrics sCheckboxMetrics;
+static ToggleGTKMetrics sRadioMetrics;
+static ToolbarGTKMetrics sToolbarMetrics;
+static CSDWindowDecorationSize sToplevelWindowDecorationSize;
+static CSDWindowDecorationSize sPopupWindowDecorationSize;
+
+using mozilla::Span;
+
+#define ARROW_UP 0
+#define ARROW_DOWN G_PI
+#define ARROW_RIGHT G_PI_2
+#define ARROW_LEFT (G_PI + G_PI_2)
+
+#if 0
+// It's used for debugging only to compare Gecko widget style with
+// the ones used by Gtk+ applications.
+static void
+style_path_print(GtkStyleContext *context)
+{
+    const GtkWidgetPath* path = gtk_style_context_get_path(context);
+
+    static auto sGtkWidgetPathToStringPtr =
+        (char * (*)(const GtkWidgetPath *))
+        dlsym(RTLD_DEFAULT, "gtk_widget_path_to_string");
+
+    fprintf(stderr, "Style path:\n%s\n\n", sGtkWidgetPathToStringPtr(path));
+}
+#endif
+
+static GtkBorder operator+=(GtkBorder& first, const GtkBorder& second) {
+  first.left += second.left;
+  first.right += second.right;
+  first.top += second.top;
+  first.bottom += second.bottom;
+  return first;
+}
+
+static gint moz_gtk_get_tab_thickness(GtkStyleContext* style);
+
+static void Inset(GdkRectangle*, const GtkBorder&);
+
+static void InsetByMargin(GdkRectangle*, GtkStyleContext* style);
+
+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_style_context_get_state(style),
+                               &margin);
+  *left += margin.left;
+  *right += margin.right;
+  *top += margin.top;
+  *bottom += margin.bottom;
+}
+
+static void moz_gtk_add_style_border(GtkStyleContext* style, gint* left,
+                                     gint* top, gint* right, gint* bottom) {
+  GtkBorder border;
+
+  gtk_style_context_get_border(style, gtk_style_context_get_state(style),
+                               &border);
+
+  *left += border.left;
+  *right += border.right;
+  *top += border.top;
+  *bottom += border.bottom;
+}
+
+static void moz_gtk_add_style_padding(GtkStyleContext* style, gint* left,
+                                      gint* top, gint* right, gint* bottom) {
+  GtkBorder padding;
+
+  gtk_style_context_get_padding(style, gtk_style_context_get_state(style),
+                                &padding);
+
+  *left += padding.left;
+  *right += padding.right;
+  *top += padding.top;
+  *bottom += padding.bottom;
+}
+
+static void moz_gtk_add_margin_border_padding(GtkStyleContext* style,
+                                              gint* left, gint* top,
+                                              gint* right, gint* bottom) {
+  moz_gtk_add_style_margin(style, left, top, right, bottom);
+  moz_gtk_add_style_border(style, left, top, right, bottom);
+  moz_gtk_add_style_padding(style, left, top, right, bottom);
+}
+
+static void moz_gtk_add_border_padding(GtkStyleContext* style, gint* left,
+                                       gint* top, gint* right, gint* bottom) {
+  moz_gtk_add_style_border(style, left, top, right, bottom);
+  moz_gtk_add_style_padding(style, left, top, right, bottom);
+}
+
+// In case there's an error in Gtk theme and preferred size is zero,
+// return some sane values to pass mozilla automation tests.
+// It should not happen in real-life.
+#define MIN_WIDGET_SIZE 10
+static void moz_gtk_sanity_preferred_size(GtkRequisition* requisition) {
+  if (requisition->width <= 0) {
+    requisition->width = MIN_WIDGET_SIZE;
+  }
+  if (requisition->height <= 0) {
+    requisition->height = MIN_WIDGET_SIZE;
+  }
+}
+
+// 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
+// flags.  Failure to restrict the flags in the same way as GTK can cause
+// generic CSS selectors from some themes to unintentionally match elements
+// that are not expected to change appearance on hover or mouse-down.
+static GtkStateFlags GetStateFlagsFromGtkWidgetState(GtkWidgetState* state) {
+  GtkStateFlags stateFlags = GTK_STATE_FLAG_NORMAL;
+
+  if (state->disabled)
+    stateFlags = GTK_STATE_FLAG_INSENSITIVE;
+  else {
+    if (state->depressed || state->active)
+      stateFlags =
+          static_cast<GtkStateFlags>(stateFlags | GTK_STATE_FLAG_ACTIVE);
+    if (state->inHover)
+      stateFlags =
+          static_cast<GtkStateFlags>(stateFlags | GTK_STATE_FLAG_PRELIGHT);
+    if (state->focused)
+      stateFlags =
+          static_cast<GtkStateFlags>(stateFlags | GTK_STATE_FLAG_FOCUSED);
+    if (state->backdrop)
+      stateFlags =
+          static_cast<GtkStateFlags>(stateFlags | GTK_STATE_FLAG_BACKDROP);
+  }
+
+  return stateFlags;
+}
+
+static GtkStateFlags GetStateFlagsFromGtkTabFlags(GtkTabFlags flags) {
+  return ((flags & MOZ_GTK_TAB_SELECTED) == 0) ? GTK_STATE_FLAG_NORMAL
+                                               : GTK_STATE_FLAG_ACTIVE;
+}
+
+gint moz_gtk_init() {
+  if (gtk_major_version > 3 ||
+      (gtk_major_version == 3 && gtk_minor_version >= 14))
+    checkbox_check_state = GTK_STATE_FLAG_CHECKED;
+  else
+    checkbox_check_state = GTK_STATE_FLAG_ACTIVE;
+
+  moz_gtk_refresh();
+
+  return MOZ_GTK_SUCCESS;
+}
+
+void moz_gtk_refresh() {
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    // Deprecated for Gtk >= 3.20+
+    GtkStyleContext* style = GetStyleContext(MOZ_GTK_TAB_TOP);
+    gtk_style_context_get_style(style, "has-tab-gap", &notebook_has_tab_gap,
+                                NULL);
+  } else {
+    notebook_has_tab_gap = true;
+  }
+
+  sCheckboxMetrics.initialized = false;
+  sRadioMetrics.initialized = false;
+  sToolbarMetrics.initialized = false;
+  sToplevelWindowDecorationSize.initialized = false;
+  sPopupWindowDecorationSize.initialized = false;
+
+  /* This will destroy all of our widgets */
+  ResetWidgetCache();
+}
+
+gint moz_gtk_button_get_default_overflow(gint* border_top, gint* border_left,
+                                         gint* border_bottom,
+                                         gint* border_right) {
+  GtkBorder* default_outside_border;
+
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_BUTTON);
+  gtk_style_context_get_style(style, "default-outside-border",
+                              &default_outside_border, NULL);
+
+  if (default_outside_border) {
+    *border_top = default_outside_border->top;
+    *border_left = default_outside_border->left;
+    *border_bottom = default_outside_border->bottom;
+    *border_right = default_outside_border->right;
+    gtk_border_free(default_outside_border);
+  } else {
+    *border_top = *border_left = *border_bottom = *border_right = 0;
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_button_get_default_border(gint* border_top,
+                                              gint* border_left,
+                                              gint* border_bottom,
+                                              gint* border_right) {
+  GtkBorder* default_border;
+
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_BUTTON);
+  gtk_style_context_get_style(style, "default-border", &default_border, NULL);
+
+  if (default_border) {
+    *border_top = default_border->top;
+    *border_left = default_border->left;
+    *border_bottom = default_border->bottom;
+    *border_right = default_border->right;
+    gtk_border_free(default_border);
+  } else {
+    /* see gtkbutton.c */
+    *border_top = *border_left = *border_bottom = *border_right = 1;
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_splitter_get_metrics(gint orientation, gint* size) {
+  GtkStyleContext* style;
+  if (orientation == GTK_ORIENTATION_HORIZONTAL) {
+    style = GetStyleContext(MOZ_GTK_SPLITTER_HORIZONTAL);
+  } else {
+    style = GetStyleContext(MOZ_GTK_SPLITTER_VERTICAL);
+  }
+  gtk_style_context_get_style(style, "handle_size", size, NULL);
+  return MOZ_GTK_SUCCESS;
+}
+
+static void CalculateToolbarButtonMetrics(WidgetNodeType aAppearance,
+                                          ToolbarButtonGTKMetrics* aMetrics) {
+  gint iconWidth, iconHeight;
+  if (!gtk_icon_size_lookup(GTK_ICON_SIZE_MENU, &iconWidth, &iconHeight)) {
+    NS_WARNING("Failed to get Gtk+ icon size for titlebar button!");
+
+    // Use some reasonable fallback size
+    iconWidth = 16;
+    iconHeight = 16;
+  }
+
+  GtkStyleContext* style = GetStyleContext(aAppearance);
+  gint width = 0, height = 0;
+  if (!gtk_check_version(3, 20, 0)) {
+    gtk_style_context_get(style, gtk_style_context_get_state(style),
+                          "min-width", &width, "min-height", &height, NULL);
+  }
+
+  // Cover cases when min-width/min-height is not set, it's invalid
+  // or we're running on Gtk+ < 3.20.
+  if (width < iconWidth) width = iconWidth;
+  if (height < iconHeight) height = iconHeight;
+
+  gint left = 0, top = 0, right = 0, bottom = 0;
+  moz_gtk_add_border_padding(style, &left, &top, &right, &bottom);
+
+  // Button size is calculated as min-width/height + border/padding.
+  width += left + right;
+  height += top + bottom;
+
+  // Place icon at button center.
+  aMetrics->iconXPosition = (width - iconWidth) / 2;
+  aMetrics->iconYPosition = (height - iconHeight) / 2;
+
+  aMetrics->minSizeWithBorderMargin.width = width;
+  aMetrics->minSizeWithBorderMargin.height = height;
+}
+
+// We support LTR layout only here for now.
+static void CalculateToolbarButtonSpacing(WidgetNodeType aAppearance,
+                                          ToolbarButtonGTKMetrics* aMetrics) {
+  GtkStyleContext* style = GetStyleContext(aAppearance);
+  gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                               &aMetrics->buttonMargin);
+
+  // Get titlebar spacing, a default one is 6 pixels (gtk/gtkheaderbar.c)
+  gint buttonSpacing = 6;
+  g_object_get(GetWidget(MOZ_GTK_HEADER_BAR), "spacing", &buttonSpacing,
+               nullptr);
+
+  // We apply spacing as a margin equally to both adjacent buttons.
+  buttonSpacing /= 2;
+
+  if (!aMetrics->firstButton) {
+    aMetrics->buttonMargin.left += buttonSpacing;
+  }
+  if (!aMetrics->lastButton) {
+    aMetrics->buttonMargin.right += buttonSpacing;
+  }
+
+  aMetrics->minSizeWithBorderMargin.width +=
+      aMetrics->buttonMargin.right + aMetrics->buttonMargin.left;
+  aMetrics->minSizeWithBorderMargin.height +=
+      aMetrics->buttonMargin.top + aMetrics->buttonMargin.bottom;
+}
+
+size_t GetGtkHeaderBarButtonLayout(Span<ButtonLayout> aButtonLayout,
+                                   bool* aReversedButtonsPlacement) {
+  gchar* decorationLayoutSetting = nullptr;
+  GtkSettings* settings = gtk_settings_get_default();
+  g_object_get(settings, "gtk-decoration-layout", &decorationLayoutSetting,
+               nullptr);
+  auto free = mozilla::MakeScopeExit([&] { g_free(decorationLayoutSetting); });
+
+  // Use a default layout
+  const gchar* decorationLayout = "menu:minimize,maximize,close";
+  if (decorationLayoutSetting) {
+    decorationLayout = decorationLayoutSetting;
+  }
+
+  // "minimize,maximize,close:" layout means buttons are on the opposite
+  // titlebar side. close button is always there.
+  if (aReversedButtonsPlacement) {
+    const char* closeButton = strstr(decorationLayout, "close");
+    const char* separator = strchr(decorationLayout, ':');
+    *aReversedButtonsPlacement =
+        closeButton && separator && closeButton < separator;
+  }
+
+  // We check what position a button string is stored in decorationLayout.
+  //
+  // decorationLayout gets its value from the GNOME preference:
+  // org.gnome.desktop.vm.preferences.button-layout via the
+  // gtk-decoration-layout property.
+  //
+  // Documentation of the gtk-decoration-layout property can be found here:
+  // https://developer.gnome.org/gtk3/stable/GtkSettings.html#GtkSettings--gtk-decoration-layout
+  if (aButtonLayout.IsEmpty()) {
+    return 0;
+  }
+
+  nsDependentCSubstring layout(decorationLayout, strlen(decorationLayout));
+
+  size_t activeButtons = 0;
+  for (const auto& part : layout.Split(':')) {
+    for (const auto& button : part.Split(',')) {
+      if (button.EqualsLiteral("close")) {
+        aButtonLayout[activeButtons++] = {MOZ_GTK_HEADER_BAR_BUTTON_CLOSE};
+      } else if (button.EqualsLiteral("minimize")) {
+        aButtonLayout[activeButtons++] = {MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE};
+      } else if (button.EqualsLiteral("maximize")) {
+        aButtonLayout[activeButtons++] = {MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE};
+      }
+      if (activeButtons == aButtonLayout.Length()) {
+        return activeButtons;
+      }
+    }
+  }
+  return activeButtons;
+}
+
+static void EnsureToolbarMetrics() {
+  if (sToolbarMetrics.initialized) {
+    return;
+  }
+  // Make sure we have clean cache after theme reset, etc.
+  memset(&sToolbarMetrics, 0, sizeof(sToolbarMetrics));
+
+  // Calculate titlebar button visibility and positions.
+  ButtonLayout aButtonLayout[TOOLBAR_BUTTONS];
+  size_t activeButtonNums =
+      GetGtkHeaderBarButtonLayout(Span(aButtonLayout), nullptr);
+
+  for (size_t i = 0; i < activeButtonNums; i++) {
+    int buttonIndex =
+        (aButtonLayout[i].mType - MOZ_GTK_HEADER_BAR_BUTTON_CLOSE);
+    ToolbarButtonGTKMetrics* metrics = sToolbarMetrics.button + buttonIndex;
+    metrics->visible = true;
+    // Mark first button
+    if (!i) {
+      metrics->firstButton = true;
+    }
+    // Mark last button.
+    if (i == (activeButtonNums - 1)) {
+      metrics->lastButton = true;
+    }
+
+    CalculateToolbarButtonMetrics(aButtonLayout[i].mType, metrics);
+    CalculateToolbarButtonSpacing(aButtonLayout[i].mType, metrics);
+  }
+
+  sToolbarMetrics.initialized = true;
+}
+
+const ToolbarButtonGTKMetrics* GetToolbarButtonMetrics(
+    WidgetNodeType aAppearance) {
+  EnsureToolbarMetrics();
+
+  int buttonIndex = (aAppearance - MOZ_GTK_HEADER_BAR_BUTTON_CLOSE);
+  NS_ASSERTION(buttonIndex >= 0 && buttonIndex <= TOOLBAR_BUTTONS,
+               "GetToolbarButtonMetrics(): Wrong titlebar button!");
+  return sToolbarMetrics.button + buttonIndex;
+}
+
+static gint moz_gtk_window_decoration_paint(cairo_t* cr,
+                                            const GdkRectangle* rect,
+                                            GtkWidgetState* state,
+                                            GtkTextDirection direction) {
+  if (mozilla::widget::GdkIsWaylandDisplay()) {
+    // Doesn't seem to be needed.
+    return MOZ_GTK_SUCCESS;
+  }
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* windowStyle =
+      GetStyleContext(MOZ_GTK_HEADERBAR_WINDOW, state->image_scale);
+  const bool solidDecorations =
+      gtk_style_context_has_class(windowStyle, "solid-csd");
+  GtkStyleContext* decorationStyle =
+      GetStyleContext(solidDecorations ? MOZ_GTK_WINDOW_DECORATION_SOLID
+                                       : MOZ_GTK_WINDOW_DECORATION,
+                      state->image_scale, GTK_TEXT_DIR_LTR, state_flags);
+
+  gtk_render_background(decorationStyle, cr, rect->x, rect->y, rect->width,
+                        rect->height);
+  gtk_render_frame(decorationStyle, cr, rect->x, rect->y, rect->width,
+                   rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_button_paint(cairo_t* cr, const GdkRectangle* rect,
+                                 GtkWidgetState* state, GtkReliefStyle relief,
+                                 GtkWidget* widget,
+                                 GtkTextDirection direction) {
+  if (!widget) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* style = gtk_widget_get_style_context(widget);
+  gint x = rect->x, y = rect->y, width = rect->width, height = rect->height;
+
+  gtk_widget_set_direction(widget, direction);
+
+  gtk_style_context_save(style);
+  StyleContextSetScale(style, state->image_scale);
+  gtk_style_context_set_state(style, state_flags);
+
+  if (state->isDefault && relief == GTK_RELIEF_NORMAL && !state->focused &&
+      !(state_flags & GTK_STATE_FLAG_PRELIGHT)) {
+    /* handle default borders both outside and inside the button */
+    gint default_top, default_left, default_bottom, default_right;
+    moz_gtk_button_get_default_overflow(&default_top, &default_left,
+                                        &default_bottom, &default_right);
+    x -= default_left;
+    y -= default_top;
+    width += default_left + default_right;
+    height += default_top + default_bottom;
+    gtk_render_background(style, cr, x, y, width, height);
+    gtk_render_frame(style, cr, x, y, width, height);
+    moz_gtk_button_get_default_border(&default_top, &default_left,
+                                      &default_bottom, &default_right);
+    x += default_left;
+    y += default_top;
+    width -= (default_left + default_right);
+    height -= (default_top + default_bottom);
+  } else if (relief != GTK_RELIEF_NONE || state->depressed ||
+             (state_flags & GTK_STATE_FLAG_PRELIGHT)) {
+    /* the following line can trigger an assertion (Crux theme)
+       file ../../gdk/gdkwindow.c: line 1846 (gdk_window_clear_area):
+       assertion `GDK_IS_WINDOW (window)' failed */
+    gtk_render_background(style, cr, x, y, width, height);
+    gtk_render_frame(style, cr, x, y, width, height);
+  }
+
+  if (state->focused) {
+    GtkBorder border;
+    gtk_style_context_get_border(style, state_flags, &border);
+    x += border.left;
+    y += border.top;
+    width -= (border.left + border.right);
+    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,
+                                            const GdkRectangle* aRect,
+                                            GtkWidgetState* state,
+                                            GtkReliefStyle relief,
+                                            WidgetNodeType aIconWidgetType,
+                                            GtkTextDirection direction) {
+  GdkRectangle rect = *aRect;
+  // We need to inset our calculated margin because it also
+  // contains titlebar button spacing.
+  const ToolbarButtonGTKMetrics* metrics = GetToolbarButtonMetrics(
+      aIconWidgetType == MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE
+          ? MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE
+          : aIconWidgetType);
+  Inset(&rect, metrics->buttonMargin);
+
+  GtkWidget* buttonWidget = GetWidget(aIconWidgetType);
+  if (!buttonWidget) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+  moz_gtk_button_paint(cr, &rect, state, relief, buttonWidget, direction);
+
+  GtkWidget* iconWidget =
+      gtk_bin_get_child(GTK_BIN(GetWidget(aIconWidgetType)));
+  if (!iconWidget) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+  cairo_surface_t* surface =
+      GetWidgetIconSurface(iconWidget, state->image_scale);
+
+  if (surface) {
+    GtkStyleContext* style = gtk_widget_get_style_context(buttonWidget);
+    GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+
+    gtk_style_context_save(style);
+    StyleContextSetScale(style, state->image_scale);
+    gtk_style_context_set_state(style, state_flags);
+
+    /* This is available since Gtk+ 3.10 as well as GtkHeaderBar */
+    gtk_render_icon_surface(style, cr, surface, rect.x + metrics->iconXPosition,
+                            rect.y + metrics->iconYPosition);
+    gtk_style_context_restore(style);
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+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 x, y, width, height;
+  GtkStyleContext* style;
+
+  // We need to call this before GetStyleContext, because otherwise we would
+  // reset state flags
+  const ToggleGTKMetrics* metrics =
+      GetToggleMetrics(isradio ? MOZ_GTK_RADIOBUTTON : MOZ_GTK_CHECKBUTTON);
+  // Clamp the rect and paint it center aligned in the rect.
+  x = rect->x;
+  y = rect->y;
+  width = rect->width;
+  height = rect->height;
+
+  if (rect->width < rect->height) {
+    y = rect->y + (rect->height - rect->width) / 2;
+    height = rect->width;
+  }
+
+  if (rect->height < rect->width) {
+    x = rect->x + (rect->width - rect->height) / 2;
+    width = rect->height;
+  }
+
+  if (selected)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | checkbox_check_state);
+
+  if (inconsistent)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | GTK_STATE_FLAG_INCONSISTENT);
+
+  style = GetStyleContext(isradio ? MOZ_GTK_RADIOBUTTON : MOZ_GTK_CHECKBUTTON,
+                          state->image_scale, direction, state_flags);
+
+  if (gtk_check_version(3, 20, 0) == nullptr) {
+    gtk_render_background(style, cr, x, y, width, height);
+    gtk_render_frame(style, cr, x, y, width, height);
+    // Indicator is inset by the toggle's padding and border.
+    gint indicator_x = x + metrics->borderAndPadding.left;
+    gint indicator_y = y + metrics->borderAndPadding.top;
+    gint indicator_width = metrics->minSizeWithBorder.width -
+                           metrics->borderAndPadding.left -
+                           metrics->borderAndPadding.right;
+    gint indicator_height = metrics->minSizeWithBorder.height -
+                            metrics->borderAndPadding.top -
+                            metrics->borderAndPadding.bottom;
+    if (isradio) {
+      gtk_render_option(style, cr, indicator_x, indicator_y, indicator_width,
+                        indicator_height);
+    } else {
+      gtk_render_check(style, cr, indicator_x, indicator_y, indicator_width,
+                       indicator_height);
+    }
+  } else {
+    if (isradio) {
+      gtk_render_option(style, cr, x, y, width, height);
+    } else {
+      gtk_render_check(style, cr, x, y, width, height);
+    }
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint calculate_button_inner_rect(GtkWidget* button,
+                                        const GdkRectangle* rect,
+                                        GdkRectangle* inner_rect,
+                                        GtkTextDirection direction) {
+  GtkStyleContext* style;
+  GtkBorder border;
+  GtkBorder padding = {0, 0, 0, 0};
+
+  style = gtk_widget_get_style_context(button);
+
+  /* This mirrors gtkbutton's child positioning */
+  gtk_style_context_get_border(style, gtk_style_context_get_state(style),
+                               &border);
+  gtk_style_context_get_padding(style, gtk_style_context_get_state(style),
+                                &padding);
+
+  inner_rect->x = rect->x + border.left + padding.left;
+  inner_rect->y = rect->y + padding.top + border.top;
+  inner_rect->width =
+      MAX(1, rect->width - padding.left - padding.right - border.left * 2);
+  inner_rect->height =
+      MAX(1, rect->height - padding.top - padding.bottom - border.top * 2);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint calculate_arrow_rect(GtkWidget* arrow, GdkRectangle* rect,
+                                 GdkRectangle* arrow_rect,
+                                 GtkTextDirection direction) {
+  /* defined in gtkarrow.c */
+  gfloat arrow_scaling = 0.7;
+  gfloat xalign, xpad;
+  gint extent;
+  gint mxpad, mypad;
+  gfloat mxalign, myalign;
+  GtkMisc* misc = GTK_MISC(arrow);
+
+  gtk_style_context_get_style(gtk_widget_get_style_context(arrow),
+                              "arrow_scaling", &arrow_scaling, NULL);
+
+  gtk_misc_get_padding(misc, &mxpad, &mypad);
+  extent = MIN((rect->width - mxpad * 2), (rect->height - mypad * 2)) *
+           arrow_scaling;
+
+  gtk_misc_get_alignment(misc, &mxalign, &myalign);
+
+  xalign = direction == GTK_TEXT_DIR_LTR ? mxalign : 1.0 - mxalign;
+  xpad = mxpad + (rect->width - extent) * xalign;
+
+  arrow_rect->x = direction == GTK_TEXT_DIR_LTR ? floor(rect->x + xpad)
+                                                : ceil(rect->x + xpad);
+  arrow_rect->y = floor(rect->y + mypad + ((rect->height - extent) * myalign));
+
+  arrow_rect->width = arrow_rect->height = extent;
+
+  return MOZ_GTK_SUCCESS;
+}
+
+/**
+ * Get minimum widget size as sum of margin, padding, border and
+ * min-width/min-height.
+ */
+static void moz_gtk_get_widget_min_size(GtkStyleContext* style, int* width,
+                                        int* height) {
+  GtkStateFlags state_flags = gtk_style_context_get_state(style);
+  gtk_style_context_get(style, state_flags, "min-height", height, "min-width",
+                        width, nullptr);
+
+  GtkBorder border, padding, margin;
+  gtk_style_context_get_border(style, state_flags, &border);
+  gtk_style_context_get_padding(style, state_flags, &padding);
+  gtk_style_context_get_margin(style, state_flags, &margin);
+
+  *width += border.left + border.right + margin.left + margin.right +
+            padding.left + padding.right;
+  *height += border.top + border.bottom + margin.top + margin.bottom +
+             padding.top + padding.bottom;
+}
+
+static void Inset(GdkRectangle* rect, const GtkBorder& aBorder) {
+  rect->x += aBorder.left;
+  rect->y += aBorder.top;
+  rect->width -= aBorder.left + aBorder.right;
+  rect->height -= aBorder.top + aBorder.bottom;
+}
+
+// Inset a rectangle by the margins specified in a style context.
+static void InsetByMargin(GdkRectangle* rect, GtkStyleContext* style) {
+  GtkBorder margin;
+  gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                               &margin);
+  Inset(rect, margin);
+}
+
+// Inset a rectangle by the border and padding specified in a style context.
+static void InsetByBorderPadding(GdkRectangle* rect, GtkStyleContext* style) {
+  GtkStateFlags state = gtk_style_context_get_state(style);
+  GtkBorder padding, border;
+
+  gtk_style_context_get_padding(style, state, &padding);
+  Inset(rect, padding);
+  gtk_style_context_get_border(style, state, &border);
+  Inset(rect, border);
+}
+
+static void moz_gtk_draw_styled_frame(GtkStyleContext* style, cairo_t* cr,
+                                      const GdkRectangle* aRect,
+                                      bool drawFocus) {
+  GdkRectangle rect = *aRect;
+
+  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);
+  if (drawFocus) {
+    gtk_render_focus(style, cr, rect.x, rect.y, rect.width, rect.height);
+  }
+}
+
+static gint moz_gtk_inner_spin_paint(cairo_t* cr, GdkRectangle* rect,
+                                     GtkWidgetState* state,
+                                     GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPINBUTTON, state->image_scale, direction,
+                      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);
+
+  /* hard code these values */
+  GdkRectangle arrow_rect;
+  arrow_rect.width = 6;
+  arrow_rect.height = 6;
+
+  // align spin to the left
+  arrow_rect.x = rect->x;
+
+  // up button
+  arrow_rect.y = rect->y + (rect->height - arrow_rect.height) / 2 - 3;
+  gtk_render_arrow(style, cr, ARROW_UP, arrow_rect.x, arrow_rect.y,
+                   arrow_rect.width);
+
+  // down button
+  arrow_rect.y = rect->y + (rect->height - arrow_rect.height) / 2 + 3;
+  gtk_render_arrow(style, cr, ARROW_DOWN, arrow_rect.x, arrow_rect.y,
+                   arrow_rect.width);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_spin_paint(cairo_t* cr, GdkRectangle* rect,
+                               GtkWidgetState* state,
+                               GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPINBUTTON, state->image_scale, direction);
+  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_spin_updown_paint(cairo_t* cr, GdkRectangle* rect,
+                                      gboolean isDown, GtkWidgetState* state,
+                                      GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPINBUTTON, state->image_scale, direction,
+                      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);
+
+  /* hard code these values */
+  GdkRectangle arrow_rect;
+  arrow_rect.width = 6;
+  arrow_rect.height = 6;
+  arrow_rect.x = rect->x + (rect->width - arrow_rect.width) / 2;
+  arrow_rect.y = rect->y + (rect->height - arrow_rect.height) / 2;
+  arrow_rect.y += isDown ? -1 : 1;
+
+  gtk_render_arrow(style, cr, isDown ? ARROW_DOWN : ARROW_UP, arrow_rect.x,
+                   arrow_rect.y, arrow_rect.width);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+/* See gtk_range_draw() for reference.
+ */
+static gint moz_gtk_scale_paint(cairo_t* cr, GdkRectangle* rect,
+                                GtkWidgetState* state, GtkOrientation flags,
+                                GtkTextDirection direction) {
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  gint x, y, width, height, min_width, min_height;
+  GtkStyleContext* style;
+  GtkBorder margin;
+
+  moz_gtk_get_scale_metrics(flags, &min_width, &min_height);
+
+  WidgetNodeType widget = (flags == GTK_ORIENTATION_HORIZONTAL)
+                              ? MOZ_GTK_SCALE_TROUGH_HORIZONTAL
+                              : MOZ_GTK_SCALE_TROUGH_VERTICAL;
+  style = GetStyleContext(widget, state->image_scale, direction, state_flags);
+  gtk_style_context_get_margin(style, state_flags, &margin);
+
+  // Clamp the dimension perpendicular to the direction that the slider crosses
+  // to the minimum size.
+  if (flags == GTK_ORIENTATION_HORIZONTAL) {
+    width = rect->width - (margin.left + margin.right);
+    height = min_height - (margin.top + margin.bottom);
+    x = rect->x + margin.left;
+    y = rect->y + (rect->height - height) / 2;
+  } else {
+    width = min_width - (margin.left + margin.right);
+    height = rect->height - (margin.top + margin.bottom);
+    x = rect->x + (rect->width - width) / 2;
+    y = rect->y + margin.top;
+  }
+
+  gtk_render_background(style, cr, x, y, width, height);
+  gtk_render_frame(style, cr, x, y, width, height);
+
+  if (state->focused)
+    gtk_render_focus(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_scale_thumb_paint(cairo_t* cr, GdkRectangle* rect,
+                                      GtkWidgetState* state,
+                                      GtkOrientation flags,
+                                      GtkTextDirection direction) {
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* style;
+  gint thumb_width, thumb_height, x, y;
+
+  /* determine the thumb size, and position the thumb in the center in the
+   * opposite axis
+   */
+  if (flags == GTK_ORIENTATION_HORIZONTAL) {
+    moz_gtk_get_scalethumb_metrics(GTK_ORIENTATION_HORIZONTAL, &thumb_width,
+                                   &thumb_height);
+    x = rect->x;
+    y = rect->y + (rect->height - thumb_height) / 2;
+  } else {
+    moz_gtk_get_scalethumb_metrics(GTK_ORIENTATION_VERTICAL, &thumb_height,
+                                   &thumb_width);
+    x = rect->x + (rect->width - thumb_width) / 2;
+    y = rect->y;
+  }
+
+  WidgetNodeType widget = (flags == GTK_ORIENTATION_HORIZONTAL)
+                              ? MOZ_GTK_SCALE_THUMB_HORIZONTAL
+                              : MOZ_GTK_SCALE_THUMB_VERTICAL;
+  style = GetStyleContext(widget, state->image_scale, direction, state_flags);
+  gtk_render_slider(style, cr, x, y, thumb_width, thumb_height, flags);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_hpaned_paint(cairo_t* cr, GdkRectangle* rect,
+                                 GtkWidgetState* state) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPLITTER_SEPARATOR_HORIZONTAL, state->image_scale,
+                      GTK_TEXT_DIR_LTR, GetStateFlagsFromGtkWidgetState(state));
+  gtk_render_handle(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_vpaned_paint(cairo_t* cr, GdkRectangle* rect,
+                                 GtkWidgetState* state) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPLITTER_SEPARATOR_VERTICAL, state->image_scale,
+                      GTK_TEXT_DIR_LTR, GetStateFlagsFromGtkWidgetState(state));
+  gtk_render_handle(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+// See gtk_entry_draw() for reference.
+static gint moz_gtk_entry_paint(cairo_t* cr, const GdkRectangle* aRect,
+                                GtkWidgetState* state, GtkStyleContext* style,
+                                WidgetNodeType widget) {
+  GdkRectangle rect = *aRect;
+  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
+
+  // Paint the border, except for 'menulist-textfield' that isn't focused:
+  if (widget != MOZ_GTK_DROPDOWN_ENTRY || state->focused) {
+    gtk_render_frame(style, cr, rect.x, rect.y, rect.width, rect.height);
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_text_view_paint(cairo_t* cr, GdkRectangle* aRect,
+                                    GtkWidgetState* state,
+                                    GtkTextDirection direction) {
+  // GtkTextView and GtkScrolledWindow do not set active and prelight flags.
+  // The use of focus with MOZ_GTK_SCROLLED_WINDOW here is questionable
+  // because a parent widget will not have focus when its child GtkTextView
+  // has focus, but perhaps this may help identify a focused textarea with
+  // some themes as GtkTextView backgrounds do not typically render
+  // differently with focus.
+  GtkStateFlags state_flags = state->disabled  ? GTK_STATE_FLAG_INSENSITIVE
+                              : state->focused ? GTK_STATE_FLAG_FOCUSED
+                                               : GTK_STATE_FLAG_NORMAL;
+
+  GtkStyleContext* style_frame = GetStyleContext(
+      MOZ_GTK_SCROLLED_WINDOW, state->image_scale, direction, state_flags);
+  gtk_render_frame(style_frame, cr, aRect->x, aRect->y, aRect->width,
+                   aRect->height);
+
+  GdkRectangle rect = *aRect;
+  InsetByBorderPadding(&rect, style_frame);
+
+  GtkStyleContext* style = GetStyleContext(
+      MOZ_GTK_TEXT_VIEW, state->image_scale, direction, state_flags);
+  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
+  // There is a separate "text" window, which usually provides the
+  // background behind the text.  However, this is transparent in Ambiance
+  // for GTK 3.20, in which case the MOZ_GTK_TEXT_VIEW background is
+  // visible.
+  style = GetStyleContext(MOZ_GTK_TEXT_VIEW_TEXT, state->image_scale, direction,
+                          state_flags);
+  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_treeview_paint(cairo_t* cr, GdkRectangle* rect,
+                                   GtkWidgetState* state,
+                                   GtkTextDirection direction) {
+  gint xthickness, ythickness;
+  GtkStyleContext* style;
+  GtkStyleContext* style_tree;
+  GtkStateFlags state_flags;
+  GtkBorder border;
+
+  /* only handle disabled and normal states, otherwise the whole background
+   * area will be painted differently with other states */
+  state_flags =
+      state->disabled ? GTK_STATE_FLAG_INSENSITIVE : GTK_STATE_FLAG_NORMAL;
+
+  style =
+      GetStyleContext(MOZ_GTK_SCROLLED_WINDOW, state->image_scale, direction);
+  gtk_style_context_get_border(style, state_flags, &border);
+  xthickness = border.left;
+  ythickness = border.top;
+
+  style_tree =
+      GetStyleContext(MOZ_GTK_TREEVIEW_VIEW, state->image_scale, direction);
+  gtk_render_background(style_tree, cr, rect->x + xthickness,
+                        rect->y + ythickness, rect->width - 2 * xthickness,
+                        rect->height - 2 * ythickness);
+
+  style =
+      GetStyleContext(MOZ_GTK_SCROLLED_WINDOW, state->image_scale, direction);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_tree_header_cell_paint(cairo_t* cr,
+                                           const GdkRectangle* aRect,
+                                           GtkWidgetState* state,
+                                           gboolean isSorted,
+                                           GtkTextDirection direction) {
+  moz_gtk_button_paint(cr, aRect, state, GTK_RELIEF_NORMAL,
+                       GetWidget(MOZ_GTK_TREE_HEADER_CELL), direction);
+  return MOZ_GTK_SUCCESS;
+}
+
+/* See gtk_expander_paint() for reference.
+ */
+static gint moz_gtk_treeview_expander_paint(cairo_t* cr, GdkRectangle* rect,
+                                            GtkWidgetState* state,
+                                            GtkExpanderStyle expander_state,
+                                            GtkTextDirection direction) {
+  /* Because the frame we get is of the entire treeview, we can't get the
+   * precise event state of one expander, thus rendering hover and active
+   * feedback useless. */
+  GtkStateFlags state_flags =
+      state->disabled ? GTK_STATE_FLAG_INSENSITIVE : GTK_STATE_FLAG_NORMAL;
+
+  if (state->inHover)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | GTK_STATE_FLAG_PRELIGHT);
+  if (state->selected)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | GTK_STATE_FLAG_SELECTED);
+
+  /* GTK_STATE_FLAG_ACTIVE controls expanded/colapsed state rendering
+   * in gtk_render_expander()
+   */
+  if (expander_state == GTK_EXPANDER_EXPANDED)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | checkbox_check_state);
+  else
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags & ~(checkbox_check_state));
+
+  GtkStyleContext* style = GetStyleContext(
+      MOZ_GTK_TREEVIEW_EXPANDER, state->image_scale, direction, state_flags);
+  gtk_render_expander(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+/* See gtk_separator_draw() for reference.
+ */
+static gint moz_gtk_combo_box_paint(cairo_t* cr, const GdkRectangle* aRect,
+                                    GtkWidgetState* state,
+                                    GtkTextDirection direction) {
+  GdkRectangle arrow_rect, real_arrow_rect;
+  gint separator_width;
+  gboolean wide_separators;
+  GtkStyleContext* style;
+  GtkRequisition arrow_req;
+
+  GtkWidget* comboBoxButton = GetWidget(MOZ_GTK_COMBOBOX_BUTTON);
+  GtkWidget* comboBoxArrow = GetWidget(MOZ_GTK_COMBOBOX_ARROW);
+  if (!comboBoxButton || !comboBoxArrow) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+
+  /* Also sets the direction on gComboBoxButtonWidget, which is then
+   * inherited by the separator and arrow */
+  moz_gtk_button_paint(cr, aRect, state, GTK_RELIEF_NORMAL, comboBoxButton,
+                       direction);
+
+  calculate_button_inner_rect(comboBoxButton, aRect, &arrow_rect, direction);
+  /* Now arrow_rect contains the inner rect ; we want to correct the width
+   * to what the arrow needs (see gtk_combo_box_size_allocate) */
+  gtk_widget_get_preferred_size(comboBoxArrow, NULL, &arrow_req);
+  moz_gtk_sanity_preferred_size(&arrow_req);
+
+  if (direction == GTK_TEXT_DIR_LTR)
+    arrow_rect.x += arrow_rect.width - arrow_req.width;
+  arrow_rect.width = arrow_req.width;
+
+  calculate_arrow_rect(comboBoxArrow, &arrow_rect, &real_arrow_rect, direction);
+
+  style = GetStyleContext(MOZ_GTK_COMBOBOX_ARROW, state->image_scale);
+  gtk_render_arrow(style, cr, ARROW_DOWN, real_arrow_rect.x, real_arrow_rect.y,
+                   real_arrow_rect.width);
+
+  /* If there is no separator in the theme, there's nothing left to do. */
+  GtkWidget* widget = GetWidget(MOZ_GTK_COMBOBOX_SEPARATOR);
+  if (!widget) {
+    return MOZ_GTK_SUCCESS;
+  }
+  style = gtk_widget_get_style_context(widget);
+  StyleContextSetScale(style, state->image_scale);
+  gtk_style_context_get_style(style, "wide-separators", &wide_separators,
+                              "separator-width", &separator_width, NULL);
+
+  if (wide_separators) {
+    if (direction == GTK_TEXT_DIR_LTR)
+      arrow_rect.x -= separator_width;
+    else
+      arrow_rect.x += arrow_rect.width;
+
+    gtk_render_frame(style, cr, arrow_rect.x, arrow_rect.y, separator_width,
+                     arrow_rect.height);
+  } else {
+    if (direction == GTK_TEXT_DIR_LTR) {
+      GtkBorder padding;
+      GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+      gtk_style_context_get_padding(style, state_flags, &padding);
+      arrow_rect.x -= padding.left;
+    } else
+      arrow_rect.x += arrow_rect.width;
+
+    gtk_render_line(style, cr, arrow_rect.x, arrow_rect.y, arrow_rect.x,
+                    arrow_rect.y + arrow_rect.height);
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_arrow_paint(cairo_t* cr, GdkRectangle* rect,
+                                GtkWidgetState* state, GtkArrowType arrow_type,
+                                GtkTextDirection direction) {
+  GdkRectangle arrow_rect;
+  gdouble arrow_angle;
+
+  if (direction == GTK_TEXT_DIR_RTL) {
+    if (arrow_type == GTK_ARROW_LEFT) {
+      arrow_type = GTK_ARROW_RIGHT;
+    } else if (arrow_type == GTK_ARROW_RIGHT) {
+      arrow_type = GTK_ARROW_LEFT;
+    }
+  }
+  switch (arrow_type) {
+    case GTK_ARROW_LEFT:
+      arrow_angle = ARROW_LEFT;
+      break;
+    case GTK_ARROW_RIGHT:
+      arrow_angle = ARROW_RIGHT;
+      break;
+    case GTK_ARROW_DOWN:
+      arrow_angle = ARROW_DOWN;
+      break;
+    default:
+      arrow_angle = ARROW_UP;
+      break;
+  }
+  if (arrow_type == GTK_ARROW_NONE) return MOZ_GTK_SUCCESS;
+
+  GtkWidget* widget = GetWidget(MOZ_GTK_BUTTON_ARROW);
+  if (!widget) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+  calculate_arrow_rect(widget, rect, &arrow_rect, direction);
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* style = GetStyleContext(
+      MOZ_GTK_BUTTON_ARROW, state->image_scale, direction, state_flags);
+  gtk_render_arrow(style, cr, arrow_angle, arrow_rect.x, arrow_rect.y,
+                   arrow_rect.width);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_tooltip_paint(cairo_t* cr, const GdkRectangle* aRect,
+                                  GtkWidgetState* state,
+                                  GtkTextDirection direction) {
+  // Tooltip widget is made in GTK3 as following tree:
+  // Tooltip window
+  //   Horizontal Box
+  //     Icon (not supported by Firefox)
+  //     Label
+  // Each element can be fully styled by CSS of GTK theme.
+  // We have to draw all elements with appropriate offset and right dimensions.
+
+  // Tooltip drawing
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_TOOLTIP, state->image_scale, direction);
+  GdkRectangle rect = *aRect;
+  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);
+
+  // Horizontal Box drawing
+  //
+  // The box element has hard-coded 6px margin-* GtkWidget properties, which
+  // are added between the window dimensions and the CSS margin box of the
+  // horizontal box.  The frame of the tooltip window is drawn in the
+  // 6px margin.
+  // For drawing Horizontal Box we have to inset drawing area by that 6px
+  // plus its CSS margin.
+  GtkStyleContext* boxStyle =
+      GetStyleContext(MOZ_GTK_TOOLTIP_BOX, state->image_scale, direction);
+
+  rect.x += 6;
+  rect.y += 6;
+  rect.width -= 12;
+  rect.height -= 12;
+
+  InsetByMargin(&rect, boxStyle);
+  gtk_render_background(boxStyle, cr, rect.x, rect.y, rect.width, rect.height);
+  gtk_render_frame(boxStyle, cr, rect.x, rect.y, rect.width, rect.height);
+
+  // Label drawing
+  InsetByBorderPadding(&rect, boxStyle);
+
+  GtkStyleContext* labelStyle =
+      GetStyleContext(MOZ_GTK_TOOLTIP_BOX_LABEL, state->image_scale, direction);
+  moz_gtk_draw_styled_frame(labelStyle, cr, &rect, false);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_resizer_paint(cairo_t* cr, GdkRectangle* rect,
+                                  GtkWidgetState* state,
+                                  GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_RESIZER, state->image_scale, GTK_TEXT_DIR_LTR,
+                      GetStateFlagsFromGtkWidgetState(state));
+
+  // Workaround unico not respecting the text direction for resizers.
+  // See bug 1174248.
+  cairo_save(cr);
+  if (direction == GTK_TEXT_DIR_RTL) {
+    cairo_matrix_t mat;
+    cairo_matrix_init_translate(&mat, 2 * rect->x + rect->width, 0);
+    cairo_matrix_scale(&mat, -1, 1);
+    cairo_transform(cr, &mat);
+  }
+
+  gtk_render_handle(style, cr, rect->x, rect->y, rect->width, rect->height);
+  cairo_restore(cr);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_frame_paint(cairo_t* cr, GdkRectangle* rect,
+                                GtkWidgetState* state,
+                                GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_FRAME, state->image_scale, direction);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_progressbar_paint(cairo_t* cr, GdkRectangle* rect,
+                                      GtkWidgetState* state,
+                                      GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_PROGRESS_TROUGH, state->image_scale, direction);
+  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_progress_chunk_paint(cairo_t* cr, GdkRectangle* rect,
+                                         GtkWidgetState* state,
+                                         GtkTextDirection direction,
+                                         WidgetNodeType widget) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_PROGRESS_CHUNK, state->image_scale, direction);
+
+  if (widget == MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE ||
+      widget == MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE) {
+    /**
+     * The bar's size and the bar speed are set depending of the progress'
+     * size. These could also be constant for all progress bars easily.
+     */
+    gboolean vertical =
+        (widget == MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE);
+
+    /* The size of the dimension we are going to use for the animation. */
+    const gint progressSize = vertical ? rect->height : rect->width;
+
+    /* The bar is using a fifth of the element size, based on GtkProgressBar
+     * activity-blocks property. */
+    const gint barSize = MAX(1, progressSize / 5);
+
+    /* Represents the travel that has to be done for a complete cycle. */
+    const gint travel = 2 * (progressSize - barSize);
+
+    /* period equals to travel / pixelsPerMillisecond
+     * where pixelsPerMillisecond equals progressSize / 1000.0.
+     * This is equivalent to 1600. */
+    static const guint period = 1600;
+    const gint t = PR_IntervalToMilliseconds(PR_IntervalNow()) % period;
+    const gint dx = travel * t / period;
+
+    if (vertical) {
+      rect->y += (dx < travel / 2) ? dx : travel - dx;
+      rect->height = barSize;
+    } else {
+      rect->x += (dx < travel / 2) ? dx : travel - dx;
+      rect->width = barSize;
+    }
+  }
+
+  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_get_tab_thickness(GtkStyleContext* style) {
+  if (!notebook_has_tab_gap)
+    return 0; /* tabs do not overdraw the tabpanel border with "no gap" style */
+
+  GtkBorder border;
+  gtk_style_context_get_border(style, gtk_style_context_get_state(style),
+                               &border);
+  if (border.top < 2) return 2; /* some themes don't set ythickness correctly */
+
+  return border.top;
+}
+
+gint moz_gtk_get_tab_thickness(WidgetNodeType aNodeType) {
+  GtkStyleContext* style = GetStyleContext(aNodeType);
+  int thickness = moz_gtk_get_tab_thickness(style);
+  return thickness;
+}
+
+/* actual small tabs */
+static gint moz_gtk_tab_paint(cairo_t* cr, GdkRectangle* rect,
+                              GtkWidgetState* state, GtkTabFlags flags,
+                              GtkTextDirection direction,
+                              WidgetNodeType widget) {
+  /* When the tab isn't selected, we just draw a notebook extension.
+   * When it is selected, we overwrite the adjacent border of the tabpanel
+   * touching the tab with a pierced border (called "the gap") to make the
+   * tab appear physically attached to the tabpanel; see details below. */
+
+  GtkStyleContext* style;
+  GdkRectangle tabRect;
+  GdkRectangle focusRect;
+  GdkRectangle backRect;
+  int initial_gap = 0;
+  bool isBottomTab = (widget == MOZ_GTK_TAB_BOTTOM);
+
+  style = GetStyleContext(widget, state->image_scale, direction,
+                          GetStateFlagsFromGtkTabFlags(flags));
+  tabRect = *rect;
+
+  if (flags & MOZ_GTK_TAB_FIRST) {
+    gtk_style_context_get_style(style, "initial-gap", &initial_gap, NULL);
+    tabRect.width -= initial_gap;
+
+    if (direction != GTK_TEXT_DIR_RTL) {
+      tabRect.x += initial_gap;
+    }
+  }
+
+  focusRect = backRect = tabRect;
+
+  if (notebook_has_tab_gap) {
+    if ((flags & MOZ_GTK_TAB_SELECTED) == 0) {
+      /* Only draw the tab */
+      gtk_render_extension(style, cr, tabRect.x, tabRect.y, tabRect.width,
+                           tabRect.height,
+                           isBottomTab ? GTK_POS_TOP : GTK_POS_BOTTOM);
+    } else {
+      /* Draw the tab and the gap
+       * We want the gap to be positioned exactly on the tabpanel top
+       * border; since tabbox.css may set a negative margin so that the tab
+       * frame rect already overlaps the tabpanel frame rect, we need to take
+       * that into account when drawing. To that effect, nsNativeThemeGTK
+       * passes us this negative margin (bmargin in the graphic below) in the
+       * lowest bits of |flags|.  We use it to set gap_voffset, the distance
+       * between the top of the gap and the bottom of the tab (resp. the
+       * bottom of the gap and the top of the tab when we draw a bottom tab),
+       * while ensuring that the gap always touches the border of the tab,
+       * i.e. 0 <= gap_voffset <= gap_height, to avoid surprinsing results
+       * with big negative or positive margins.
+       * Here is a graphical explanation in the case of top tabs:
+       *             ___________________________
+       *            /                           \
+       *           |            T A B            |
+       * ----------|. . . . . . . . . . . . . . .|----- top of tabpanel
+       *           :    ^       bmargin          :  ^
+       *           :    | (-negative margin,     :  |
+       *  bottom   :    v  passed in flags)      :  |       gap_height
+       *    of  -> :.............................:  |    (the size of the
+       * the tab   .       part of the gap       .  |  tabpanel top border)
+       *           .      outside of the tab     .  v
+       * ----------------------------------------------
+       *
+       * To draw the gap, we use gtk_render_frame_gap(), see comment in
+       * moz_gtk_tabpanels_paint(). This gap is made 3 * gap_height tall,
+       * which should suffice to ensure that the only visible border is the
+       * pierced one.  If the tab is in the middle, we make the box_gap begin
+       * a bit to the left of the tab and end a bit to the right, adjusting
+       * the gap position so it still is under the tab, because we want the
+       * rendering of a gap in the middle of a tabpanel.  This is the role of
+       * the gints gap_{l,r}_offset. On the contrary, if the tab is the
+       * first, we align the start border of the box_gap with the start
+       * border of the tab (left if LTR, right if RTL), by setting the
+       * appropriate offset to 0.*/
+      gint gap_loffset, gap_roffset, gap_voffset, gap_height;
+
+      /* Get height needed by the gap */
+      gap_height = moz_gtk_get_tab_thickness(style);
+
+      /* Extract gap_voffset from the first bits of flags */
+      gap_voffset = flags & MOZ_GTK_TAB_MARGIN_MASK;
+      if (gap_voffset > gap_height) gap_voffset = gap_height;
+
+      /* Set gap_{l,r}_offset to appropriate values */
+      gap_loffset = gap_roffset = 20; /* should be enough */
+      if (flags & MOZ_GTK_TAB_FIRST) {
+        if (direction == GTK_TEXT_DIR_RTL)
+          gap_roffset = initial_gap;
+        else
+          gap_loffset = initial_gap;
+      }
+
+      GtkStyleContext* panelStyle =
+          GetStyleContext(MOZ_GTK_TABPANELS, state->image_scale, direction);
+
+      if (isBottomTab) {
+        /* Draw the tab on bottom */
+        focusRect.y += gap_voffset;
+        focusRect.height -= gap_voffset;
+
+        gtk_render_extension(style, cr, tabRect.x, tabRect.y + gap_voffset,
+                             tabRect.width, tabRect.height - gap_voffset,
+                             GTK_POS_TOP);
+
+        backRect.y += (gap_voffset - gap_height);
+        backRect.height = gap_height;
+
+        /* Draw the gap; erase with background color before painting in
+         * case theme does not */
+        gtk_render_background(panelStyle, cr, backRect.x, backRect.y,
+                              backRect.width, backRect.height);
+        cairo_save(cr);
+        cairo_rectangle(cr, backRect.x, backRect.y, backRect.width,
+                        backRect.height);
+        cairo_clip(cr);
+
+        gtk_render_frame_gap(panelStyle, cr, tabRect.x - gap_loffset,
+                             tabRect.y + gap_voffset - 3 * gap_height,
+                             tabRect.width + gap_loffset + gap_roffset,
+                             3 * gap_height, GTK_POS_BOTTOM, gap_loffset,
+                             gap_loffset + tabRect.width);
+        cairo_restore(cr);
+      } else {
+        /* Draw the tab on top */
+        focusRect.height -= gap_voffset;
+        gtk_render_extension(style, cr, tabRect.x, tabRect.y, tabRect.width,
+                             tabRect.height - gap_voffset, GTK_POS_BOTTOM);
+
+        backRect.y += (tabRect.height - gap_voffset);
+        backRect.height = gap_height;
+
+        /* Draw the gap; erase with background color before painting in
+         * case theme does not */
+        gtk_render_background(panelStyle, cr, backRect.x, backRect.y,
+                              backRect.width, backRect.height);
+
+        cairo_save(cr);
+        cairo_rectangle(cr, backRect.x, backRect.y, backRect.width,
+                        backRect.height);
+        cairo_clip(cr);
+
+        gtk_render_frame_gap(panelStyle, cr, tabRect.x - gap_loffset,
+                             tabRect.y + tabRect.height - gap_voffset,
+                             tabRect.width + gap_loffset + gap_roffset,
+                             3 * gap_height, GTK_POS_TOP, gap_loffset,
+                             gap_loffset + tabRect.width);
+        cairo_restore(cr);
+      }
+    }
+  } else {
+    gtk_render_background(style, cr, tabRect.x, tabRect.y, tabRect.width,
+                          tabRect.height);
+    gtk_render_frame(style, cr, tabRect.x, tabRect.y, tabRect.width,
+                     tabRect.height);
+  }
+
+  if (state->focused) {
+    /* Paint the focus ring */
+    GtkBorder padding;
+    gtk_style_context_get_padding(style, GetStateFlagsFromGtkWidgetState(state),
+                                  &padding);
+
+    focusRect.x += padding.left;
+    focusRect.width -= (padding.left + padding.right);
+    focusRect.y += padding.top;
+    focusRect.height -= (padding.top + padding.bottom);
+
+    gtk_render_focus(style, cr, focusRect.x, focusRect.y, focusRect.width,
+                     focusRect.height);
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+/* tab area*/
+static gint moz_gtk_tabpanels_paint(cairo_t* cr, GdkRectangle* rect,
+                                    GtkWidgetState* state,
+                                    GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_TABPANELS, state->image_scale, direction);
+  gtk_render_background(style, cr, rect->x, rect->y, rect->width, rect->height);
+  /*
+   * The gap size is not needed in moz_gtk_tabpanels_paint because
+   * the gap will be painted with the foreground tab in moz_gtk_tab_paint.
+   *
+   * However, if moz_gtk_tabpanels_paint just uses gtk_render_frame(),
+   * the theme will think that there are no tabs and may draw something
+   * different.Hence the trick of using two clip regions, and drawing the
+   * gap outside each clip region, to get the correct frame for
+   * a tabpanel with tabs.
+   */
+  /* left side */
+  cairo_save(cr);
+  cairo_rectangle(cr, rect->x, rect->y, rect->x + rect->width / 2,
+                  rect->y + rect->height);
+  cairo_clip(cr);
+  gtk_render_frame_gap(style, cr, rect->x, rect->y, rect->width, rect->height,
+                       GTK_POS_TOP, rect->width - 1, rect->width);
+  cairo_restore(cr);
+
+  /* right side */
+  cairo_save(cr);
+  cairo_rectangle(cr, rect->x + rect->width / 2, rect->y, rect->x + rect->width,
+                  rect->y + rect->height);
+  cairo_clip(cr);
+  gtk_render_frame_gap(style, cr, rect->x, rect->y, rect->width, rect->height,
+                       GTK_POS_TOP, 0, 1);
+  cairo_restore(cr);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_tab_scroll_arrow_paint(cairo_t* cr, GdkRectangle* rect,
+                                           GtkWidgetState* state,
+                                           GtkArrowType arrow_type,
+                                           GtkTextDirection direction) {
+  GtkStyleContext* style;
+  gdouble arrow_angle;
+  gint arrow_size = MIN(rect->width, rect->height);
+  gint x = rect->x + (rect->width - arrow_size) / 2;
+  gint y = rect->y + (rect->height - arrow_size) / 2;
+
+  if (direction == GTK_TEXT_DIR_RTL) {
+    arrow_type =
+        (arrow_type == GTK_ARROW_LEFT) ? GTK_ARROW_RIGHT : GTK_ARROW_LEFT;
+  }
+  switch (arrow_type) {
+    case GTK_ARROW_LEFT:
+      arrow_angle = ARROW_LEFT;
+      break;
+    case GTK_ARROW_RIGHT:
+      arrow_angle = ARROW_RIGHT;
+      break;
+    case GTK_ARROW_DOWN:
+      arrow_angle = ARROW_DOWN;
+      break;
+    default:
+      arrow_angle = ARROW_UP;
+      break;
+  }
+  if (arrow_type != GTK_ARROW_NONE) {
+    style = GetStyleContext(MOZ_GTK_TAB_SCROLLARROW, state->image_scale,
+                            direction, GetStateFlagsFromGtkWidgetState(state));
+    gtk_render_arrow(style, cr, arrow_angle, x, y, arrow_size);
+  }
+  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, state->image_scale,
+                                           GTK_TEXT_DIR_NONE, state_flags);
+
+  // Some themes like Elementary's style the container of the headerbar rather
+  // than the header bar itself.
+  if (HeaderBarShouldDrawContainer(widgetType)) {
+    auto containerType = widgetType == MOZ_GTK_HEADER_BAR
+                             ? MOZ_GTK_HEADERBAR_FIXED
+                             : MOZ_GTK_HEADERBAR_FIXED_MAXIMIZED;
+    style = GetStyleContext(containerType, state->image_scale,
+                            GTK_TEXT_DIR_NONE, state_flags);
+  }
+
+  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;
+}
+
+gint moz_gtk_get_widget_border(WidgetNodeType widget, gint* left, gint* top,
+                               gint* right, gint* bottom,
+                               // NOTE: callers depend on direction being used
+                               // only for MOZ_GTK_DROPDOWN widgets.
+                               GtkTextDirection direction) {
+  GtkWidget* w;
+  GtkStyleContext* style;
+  *left = *top = *right = *bottom = 0;
+
+  switch (widget) {
+    case MOZ_GTK_BUTTON:
+    case MOZ_GTK_TOOLBAR_BUTTON: {
+      style = GetStyleContext(MOZ_GTK_BUTTON);
+
+      *left = *top = *right = *bottom = gtk_container_get_border_width(
+          GTK_CONTAINER(GetWidget(MOZ_GTK_BUTTON)));
+
+      if (widget == MOZ_GTK_TOOLBAR_BUTTON) {
+        gtk_style_context_save(style);
+        gtk_style_context_add_class(style, "image-button");
+      }
+
+      moz_gtk_add_style_padding(style, left, top, right, bottom);
+
+      if (widget == MOZ_GTK_TOOLBAR_BUTTON) gtk_style_context_restore(style);
+
+      moz_gtk_add_style_border(style, left, top, right, bottom);
+
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_ENTRY:
+    case MOZ_GTK_DROPDOWN_ENTRY: {
+      style = GetStyleContext(widget);
+
+      // XXX: Subtract 1 pixel from the padding to account for the default
+      // padding in forms.css. See bug 1187385.
+      *left = *top = *right = *bottom = -1;
+      moz_gtk_add_border_padding(style, left, top, right, bottom);
+
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_TEXT_VIEW:
+    case MOZ_GTK_TREEVIEW: {
+      style = GetStyleContext(MOZ_GTK_SCROLLED_WINDOW);
+      moz_gtk_add_style_border(style, left, top, right, bottom);
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_TREE_HEADER_CELL: {
+      /* A Tree Header in GTK is just a different styled button
+       * It must be placed in a TreeView for getting the correct style
+       * assigned.
+       * That is why the following code is the same as for MOZ_GTK_BUTTON.
+       * */
+      *left = *top = *right = *bottom = gtk_container_get_border_width(
+          GTK_CONTAINER(GetWidget(MOZ_GTK_TREE_HEADER_CELL)));
+      style = GetStyleContext(MOZ_GTK_TREE_HEADER_CELL);
+      moz_gtk_add_border_padding(style, left, top, right, bottom);
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_DROPDOWN: {
+      /* We need to account for the arrow on the dropdown, so text
+       * doesn't come too close to the arrow, or in some cases spill
+       * into the arrow. */
+      gboolean wide_separators;
+      gint separator_width;
+      GtkRequisition arrow_req;
+      GtkBorder border;
+
+      *left = *top = *right = *bottom = gtk_container_get_border_width(
+          GTK_CONTAINER(GetWidget(MOZ_GTK_COMBOBOX_BUTTON)));
+      style = GetStyleContext(MOZ_GTK_COMBOBOX_BUTTON);
+      moz_gtk_add_border_padding(style, left, top, right, bottom);
+
+      /* If there is no separator, don't try to count its width. */
+      separator_width = 0;
+      GtkWidget* comboBoxSeparator = GetWidget(MOZ_GTK_COMBOBOX_SEPARATOR);
+      if (comboBoxSeparator) {
+        style = gtk_widget_get_style_context(comboBoxSeparator);
+        gtk_style_context_get_style(style, "wide-separators", &wide_separators,
+                                    "separator-width", &separator_width, NULL);
+
+        if (!wide_separators) {
+          gtk_style_context_get_border(
+              style, gtk_style_context_get_state(style), &border);
+          separator_width = border.left;
+        }
+      }
+
+      gtk_widget_get_preferred_size(GetWidget(MOZ_GTK_COMBOBOX_ARROW), NULL,
+                                    &arrow_req);
+      moz_gtk_sanity_preferred_size(&arrow_req);
+
+      if (direction == GTK_TEXT_DIR_RTL)
+        *left += separator_width + arrow_req.width;
+      else
+        *right += separator_width + arrow_req.width;
+
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_TABPANELS:
+      w = GetWidget(MOZ_GTK_TABPANELS);
+      break;
+    case MOZ_GTK_PROGRESSBAR:
+      w = GetWidget(MOZ_GTK_PROGRESSBAR);
+      break;
+    case MOZ_GTK_SPINBUTTON_ENTRY:
+    case MOZ_GTK_SPINBUTTON_UP:
+    case MOZ_GTK_SPINBUTTON_DOWN:
+      w = GetWidget(MOZ_GTK_SPINBUTTON);
+      break;
+    case MOZ_GTK_SCALE_HORIZONTAL:
+    case MOZ_GTK_SCALE_VERTICAL:
+      w = GetWidget(widget);
+      break;
+    case MOZ_GTK_FRAME:
+      w = GetWidget(MOZ_GTK_FRAME);
+      break;
+    case MOZ_GTK_TOOLTIP: {
+      // In GTK 3 there are 6 pixels of additional margin around the box.
+      // See details there:
+      // https://github.com/GNOME/gtk/blob/5ea69a136bd7e4970b3a800390e20314665aaed2/gtk/ui/gtktooltipwindow.ui#L11
+      *left = *right = *top = *bottom = 6;
+
+      // We also need to add margin/padding/borders from Tooltip content.
+      // Tooltip contains horizontal box, where icon and label is put.
+      // We ignore icon as long as we don't have support for it.
+      GtkStyleContext* boxStyle = GetStyleContext(MOZ_GTK_TOOLTIP_BOX);
+      moz_gtk_add_margin_border_padding(boxStyle, 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_BUTTON_BOX: {
+      style = GetStyleContext(MOZ_GTK_HEADER_BAR);
+      moz_gtk_add_border_padding(style, left, top, right, bottom);
+      *top = *bottom = 0;
+      bool leftButtonsPlacement = false;
+      GetGtkHeaderBarButtonLayout({}, &leftButtonsPlacement);
+      if (direction == GTK_TEXT_DIR_RTL) {
+        leftButtonsPlacement = !leftButtonsPlacement;
+      }
+      if (leftButtonsPlacement) {
+        *right = 0;
+      } else {
+        *left = 0;
+      }
+      return MOZ_GTK_SUCCESS;
+    }
+    /* These widgets have no borders, since they are not containers. */
+    case MOZ_GTK_SPLITTER_HORIZONTAL:
+    case MOZ_GTK_SPLITTER_VERTICAL:
+    case MOZ_GTK_CHECKBUTTON:
+    case MOZ_GTK_RADIOBUTTON:
+    case MOZ_GTK_SCALE_THUMB_HORIZONTAL:
+    case MOZ_GTK_SCALE_THUMB_VERTICAL:
+    case MOZ_GTK_PROGRESS_CHUNK:
+    case MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE:
+    case MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE:
+    case MOZ_GTK_TREEVIEW_EXPANDER:
+    case MOZ_GTK_HEADER_BAR:
+    case MOZ_GTK_HEADER_BAR_MAXIMIZED:
+    case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE:
+    /* These widgets have no borders.*/
+    case MOZ_GTK_INNER_SPIN_BUTTON:
+    case MOZ_GTK_SPINBUTTON:
+    case MOZ_GTK_WINDOW_DECORATION:
+    case MOZ_GTK_WINDOW_DECORATION_SOLID:
+    case MOZ_GTK_RESIZER:
+    case MOZ_GTK_TOOLBARBUTTON_ARROW:
+    case MOZ_GTK_TAB_SCROLLARROW:
+      return MOZ_GTK_SUCCESS;
+    default:
+      g_warning("Unsupported widget type: %d", widget);
+      return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+  /* TODO - we're still missing some widget implementations */
+  if (w) {
+    moz_gtk_add_style_border(gtk_widget_get_style_context(w), left, top, right,
+                             bottom);
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_get_tab_border(gint* left, gint* top, gint* right, gint* bottom,
+                            GtkTextDirection direction, GtkTabFlags flags,
+                            WidgetNodeType widget) {
+  GtkStyleContext* style = GetStyleContext(widget, 1, direction,
+                                           GetStateFlagsFromGtkTabFlags(flags));
+
+  *left = *top = *right = *bottom = 0;
+  moz_gtk_add_style_padding(style, left, top, right, bottom);
+
+  // Gtk >= 3.20 does not use those styles
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    int tab_curvature;
+
+    gtk_style_context_get_style(style, "tab-curvature", &tab_curvature, NULL);
+    *left += tab_curvature;
+    *right += tab_curvature;
+
+    if (flags & MOZ_GTK_TAB_FIRST) {
+      int initial_gap = 0;
+      gtk_style_context_get_style(style, "initial-gap", &initial_gap, NULL);
+      if (direction == GTK_TEXT_DIR_RTL)
+        *right += initial_gap;
+      else
+        *left += initial_gap;
+    }
+  } else {
+    GtkBorder margin;
+
+    gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                                 &margin);
+    *left += margin.left;
+    *right += margin.right;
+
+    if (flags & MOZ_GTK_TAB_FIRST) {
+      style = GetStyleContext(MOZ_GTK_NOTEBOOK_HEADER, direction);
+      gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                                   &margin);
+      *left += margin.left;
+      *right += margin.right;
+    }
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_get_tab_scroll_arrow_size(gint* width, gint* height) {
+  gint arrow_size;
+
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_TABPANELS);
+  gtk_style_context_get_style(style, "scroll-arrow-hlength", &arrow_size, NULL);
+
+  *height = *width = arrow_size;
+
+  return MOZ_GTK_SUCCESS;
+}
+
+void moz_gtk_get_arrow_size(WidgetNodeType widgetType, gint* width,
+                            gint* height) {
+  GtkWidget* widget;
+  switch (widgetType) {
+    case MOZ_GTK_DROPDOWN:
+      widget = GetWidget(MOZ_GTK_COMBOBOX_ARROW);
+      break;
+    default:
+      widget = GetWidget(MOZ_GTK_BUTTON_ARROW);
+      break;
+  }
+  if (widget) {
+    GtkRequisition requisition;
+    gtk_widget_get_preferred_size(widget, NULL, &requisition);
+    moz_gtk_sanity_preferred_size(&requisition);
+
+    *width = requisition.width;
+    *height = requisition.height;
+  } else {
+    *width = 0;
+    *height = 0;
+  }
+}
+
+gint moz_gtk_get_expander_size(gint* size) {
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_EXPANDER);
+  gtk_style_context_get_style(style, "expander-size", size, NULL);
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_get_treeview_expander_size(gint* size) {
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_TREEVIEW);
+  gtk_style_context_get_style(style, "expander-size", size, NULL);
+  return MOZ_GTK_SUCCESS;
+}
+
+void moz_gtk_get_entry_min_height(gint* min_content_height,
+                                  gint* border_padding_height) {
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_ENTRY);
+  if (!gtk_check_version(3, 20, 0)) {
+    gtk_style_context_get(style, gtk_style_context_get_state(style),
+                          "min-height", min_content_height, nullptr);
+  } else {
+    *min_content_height = 0;
+  }
+
+  GtkBorder border;
+  GtkBorder padding;
+  gtk_style_context_get_border(style, gtk_style_context_get_state(style),
+                               &border);
+  gtk_style_context_get_padding(style, gtk_style_context_get_state(style),
+                                &padding);
+
+  *border_padding_height =
+      (border.top + border.bottom + padding.top + padding.bottom);
+}
+
+void moz_gtk_get_scale_metrics(GtkOrientation orient, gint* scale_width,
+                               gint* scale_height) {
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    WidgetNodeType widget = (orient == GTK_ORIENTATION_HORIZONTAL)
+                                ? MOZ_GTK_SCALE_HORIZONTAL
+                                : MOZ_GTK_SCALE_VERTICAL;
+
+    gint thumb_length, thumb_height, trough_border;
+    moz_gtk_get_scalethumb_metrics(orient, &thumb_length, &thumb_height);
+
+    GtkStyleContext* style = GetStyleContext(widget);
+    gtk_style_context_get_style(style, "trough-border", &trough_border, NULL);
+
+    if (orient == GTK_ORIENTATION_HORIZONTAL) {
+      *scale_width = thumb_length + trough_border * 2;
+      *scale_height = thumb_height + trough_border * 2;
+    } else {
+      *scale_width = thumb_height + trough_border * 2;
+      *scale_height = thumb_length + trough_border * 2;
+    }
+  } else {
+    WidgetNodeType widget = (orient == GTK_ORIENTATION_HORIZONTAL)
+                                ? MOZ_GTK_SCALE_TROUGH_HORIZONTAL
+                                : MOZ_GTK_SCALE_TROUGH_VERTICAL;
+    moz_gtk_get_widget_min_size(GetStyleContext(widget), scale_width,
+                                scale_height);
+  }
+}
+
+gint moz_gtk_get_scalethumb_metrics(GtkOrientation orient, gint* thumb_length,
+                                    gint* thumb_height) {
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    WidgetNodeType widget = (orient == GTK_ORIENTATION_HORIZONTAL)
+                                ? MOZ_GTK_SCALE_HORIZONTAL
+                                : MOZ_GTK_SCALE_VERTICAL;
+    GtkStyleContext* style = GetStyleContext(widget);
+    gtk_style_context_get_style(style, "slider_length", thumb_length,
+                                "slider_width", thumb_height, NULL);
+  } else {
+    WidgetNodeType widget = (orient == GTK_ORIENTATION_HORIZONTAL)
+                                ? MOZ_GTK_SCALE_THUMB_HORIZONTAL
+                                : MOZ_GTK_SCALE_THUMB_VERTICAL;
+    GtkStyleContext* style = GetStyleContext(widget);
+
+    gint min_width, min_height;
+    GtkStateFlags state = gtk_style_context_get_state(style);
+    gtk_style_context_get(style, state, "min-width", &min_width, "min-height",
+                          &min_height, nullptr);
+    GtkBorder margin;
+    gtk_style_context_get_margin(style, state, &margin);
+    gint margin_width = margin.left + margin.right;
+    gint margin_height = margin.top + margin.bottom;
+
+    // Negative margin of slider element also determines its minimal size
+    // so use bigger of those two values.
+    if (min_width < -margin_width) min_width = -margin_width;
+    if (min_height < -margin_height) min_height = -margin_height;
+
+    *thumb_length = min_width;
+    *thumb_height = min_height;
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+const ToggleGTKMetrics* GetToggleMetrics(WidgetNodeType aWidgetType) {
+  ToggleGTKMetrics* metrics;
+
+  switch (aWidgetType) {
+    case MOZ_GTK_RADIOBUTTON:
+      metrics = &sRadioMetrics;
+      break;
+    case MOZ_GTK_CHECKBUTTON:
+      metrics = &sCheckboxMetrics;
+      break;
+    default:
+      MOZ_CRASH("Unsupported widget type for getting metrics");
+      return nullptr;
+  }
+
+  metrics->initialized = true;
+  if (gtk_check_version(3, 20, 0) == nullptr) {
+    GtkStyleContext* style = GetStyleContext(aWidgetType);
+    GtkStateFlags state_flags = gtk_style_context_get_state(style);
+    gtk_style_context_get(style, state_flags, "min-height",
+                          &(metrics->minSizeWithBorder.height), "min-width",
+                          &(metrics->minSizeWithBorder.width), nullptr);
+    // Fallback to indicator size if min dimensions are zero
+    if (metrics->minSizeWithBorder.height == 0 ||
+        metrics->minSizeWithBorder.width == 0) {
+      gint indicator_size = 0;
+      gtk_widget_style_get(GetWidget(MOZ_GTK_CHECKBUTTON_CONTAINER),
+                           "indicator_size", &indicator_size, nullptr);
+      if (metrics->minSizeWithBorder.height == 0) {
+        metrics->minSizeWithBorder.height = indicator_size;
+      }
+      if (metrics->minSizeWithBorder.width == 0) {
+        metrics->minSizeWithBorder.width = indicator_size;
+      }
+    }
+
+    GtkBorder border, padding;
+    gtk_style_context_get_border(style, state_flags, &border);
+    gtk_style_context_get_padding(style, state_flags, &padding);
+    metrics->borderAndPadding.left = border.left + padding.left;
+    metrics->borderAndPadding.right = border.right + padding.right;
+    metrics->borderAndPadding.top = border.top + padding.top;
+    metrics->borderAndPadding.bottom = border.bottom + padding.bottom;
+    metrics->minSizeWithBorder.width +=
+        metrics->borderAndPadding.left + metrics->borderAndPadding.right;
+    metrics->minSizeWithBorder.height +=
+        metrics->borderAndPadding.top + metrics->borderAndPadding.bottom;
+  } else {
+    gint indicator_size = 0, indicator_spacing = 0;
+    gtk_widget_style_get(GetWidget(MOZ_GTK_CHECKBUTTON_CONTAINER),
+                         "indicator_size", &indicator_size, "indicator_spacing",
+                         &indicator_spacing, nullptr);
+    metrics->minSizeWithBorder.width = metrics->minSizeWithBorder.height =
+        indicator_size;
+  }
+  return metrics;
+}
+
+/*
+ * get_shadow_width() from gtkwindow.c is not public so we need
+ * to implement it.
+ */
+void InitWindowDecorationSize(CSDWindowDecorationSize* sWindowDecorationSize,
+                              bool aPopupWindow) {
+  bool solidDecorations = gtk_style_context_has_class(
+      GetStyleContext(MOZ_GTK_HEADERBAR_WINDOW, 1), "solid-csd");
+  // solid-csd does not use frame extents, quit now.
+  if (solidDecorations) {
+    sWindowDecorationSize->decorationSize = {0, 0, 0, 0};
+    return;
+  }
+
+  // Scale factor is applied later when decoration size is used for actual
+  // gtk windows.
+  GtkStyleContext* context = GetStyleContext(MOZ_GTK_WINDOW_DECORATION);
+
+  /* Always sum border + padding */
+  GtkBorder padding;
+  GtkStateFlags state = gtk_style_context_get_state(context);
+  gtk_style_context_get_border(context, state,
+                               &sWindowDecorationSize->decorationSize);
+  gtk_style_context_get_padding(context, state, &padding);
+  sWindowDecorationSize->decorationSize += padding;
+
+  // Available on GTK 3.20+.
+  static auto sGtkRenderBackgroundGetClip = (void (*)(
+      GtkStyleContext*, gdouble, gdouble, gdouble, gdouble,
+      GdkRectangle*))dlsym(RTLD_DEFAULT, "gtk_render_background_get_clip");
+
+  if (!sGtkRenderBackgroundGetClip) {
+    return;
+  }
+
+  GdkRectangle clip;
+  sGtkRenderBackgroundGetClip(context, 0, 0, 0, 0, &clip);
+
+  GtkBorder extents;
+  extents.top = -clip.y;
+  extents.right = clip.width + clip.x;
+  extents.bottom = clip.height + clip.y;
+  extents.left = -clip.x;
+
+  // Get shadow extents but combine with style margin; use the bigger value.
+  // Margin is used for resize grip size - it's not present on
+  // popup windows.
+  if (!aPopupWindow) {
+    GtkBorder margin;
+    gtk_style_context_get_margin(context, state, &margin);
+
+    extents.top = MAX(extents.top, margin.top);
+    extents.right = MAX(extents.right, margin.right);
+    extents.bottom = MAX(extents.bottom, margin.bottom);
+    extents.left = MAX(extents.left, margin.left);
+  }
+
+  sWindowDecorationSize->decorationSize += extents;
+}
+
+GtkBorder GetCSDDecorationSize(bool aIsPopup) {
+  auto metrics =
+      aIsPopup ? &sPopupWindowDecorationSize : &sToplevelWindowDecorationSize;
+  if (!metrics->initialized) {
+    InitWindowDecorationSize(metrics, aIsPopup);
+    metrics->initialized = true;
+  }
+  return metrics->decorationSize;
+}
+
+/* cairo_t *cr argument has to be a system-cairo. */
+gint moz_gtk_widget_paint(WidgetNodeType widget, cairo_t* cr,
+                          GdkRectangle* rect, GtkWidgetState* state, gint flags,
+                          GtkTextDirection direction) {
+  /* A workaround for https://bugzilla.gnome.org/show_bug.cgi?id=694086
+   */
+  cairo_new_path(cr);
+
+  switch (widget) {
+    case MOZ_GTK_BUTTON:
+    case MOZ_GTK_TOOLBAR_BUTTON:
+      if (state->depressed) {
+        return moz_gtk_button_paint(cr, rect, state, (GtkReliefStyle)flags,
+                                    GetWidget(MOZ_GTK_TOGGLE_BUTTON),
+                                    direction);
+      }
+      return moz_gtk_button_paint(cr, rect, state, (GtkReliefStyle)flags,
+                                  GetWidget(MOZ_GTK_BUTTON), direction);
+    case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE:
+      return moz_gtk_header_bar_button_paint(
+          cr, rect, state, (GtkReliefStyle)flags, widget, direction);
+    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);
+    case MOZ_GTK_SCALE_HORIZONTAL:
+    case MOZ_GTK_SCALE_VERTICAL:
+      return moz_gtk_scale_paint(cr, rect, state, (GtkOrientation)flags,
+                                 direction);
+    case MOZ_GTK_SCALE_THUMB_HORIZONTAL:
+    case MOZ_GTK_SCALE_THUMB_VERTICAL:
+      return moz_gtk_scale_thumb_paint(cr, rect, state, (GtkOrientation)flags,
+                                       direction);
+    case MOZ_GTK_INNER_SPIN_BUTTON:
+      return moz_gtk_inner_spin_paint(cr, rect, state, direction);
+    case MOZ_GTK_SPINBUTTON:
+      return moz_gtk_spin_paint(cr, rect, state, direction);
+    case MOZ_GTK_SPINBUTTON_UP:
+    case MOZ_GTK_SPINBUTTON_DOWN:
+      return moz_gtk_spin_updown_paint(
+          cr, rect, (widget == MOZ_GTK_SPINBUTTON_DOWN), state, direction);
+    case MOZ_GTK_SPINBUTTON_ENTRY: {
+      GtkStyleContext* style =
+          GetStyleContext(MOZ_GTK_SPINBUTTON_ENTRY, state->image_scale,
+                          direction, GetStateFlagsFromGtkWidgetState(state));
+      return moz_gtk_entry_paint(cr, rect, state, style, widget);
+    }
+    case MOZ_GTK_TREEVIEW:
+      return moz_gtk_treeview_paint(cr, rect, state, direction);
+    case MOZ_GTK_TREE_HEADER_CELL:
+      return moz_gtk_tree_header_cell_paint(cr, rect, state, flags, direction);
+    case MOZ_GTK_TREEVIEW_EXPANDER:
+      return moz_gtk_treeview_expander_paint(
+          cr, rect, state, (GtkExpanderStyle)flags, direction);
+    case MOZ_GTK_ENTRY:
+    case MOZ_GTK_DROPDOWN_ENTRY: {
+      GtkStyleContext* style =
+          GetStyleContext(widget, state->image_scale, direction,
+                          GetStateFlagsFromGtkWidgetState(state));
+      gint ret = moz_gtk_entry_paint(cr, rect, state, style, widget);
+      return ret;
+    }
+    case MOZ_GTK_TEXT_VIEW:
+      return moz_gtk_text_view_paint(cr, rect, state, direction);
+    case MOZ_GTK_DROPDOWN:
+      return moz_gtk_combo_box_paint(cr, rect, state, direction);
+    case MOZ_GTK_TOOLTIP:
+      return moz_gtk_tooltip_paint(cr, rect, state, direction);
+    case MOZ_GTK_FRAME:
+      return moz_gtk_frame_paint(cr, rect, state, direction);
+    case MOZ_GTK_RESIZER:
+      return moz_gtk_resizer_paint(cr, rect, state, direction);
+    case MOZ_GTK_PROGRESSBAR:
+      return moz_gtk_progressbar_paint(cr, rect, state, direction);
+    case MOZ_GTK_PROGRESS_CHUNK:
+    case MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE:
+    case MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE:
+      return moz_gtk_progress_chunk_paint(cr, rect, state, direction, widget);
+    case MOZ_GTK_TAB_TOP:
+    case MOZ_GTK_TAB_BOTTOM:
+      return moz_gtk_tab_paint(cr, rect, state, (GtkTabFlags)flags, direction,
+                               widget);
+    case MOZ_GTK_TABPANELS:
+      return moz_gtk_tabpanels_paint(cr, rect, state, direction);
+    case MOZ_GTK_TAB_SCROLLARROW:
+      return moz_gtk_tab_scroll_arrow_paint(cr, rect, state,
+                                            (GtkArrowType)flags, direction);
+    case MOZ_GTK_TOOLBARBUTTON_ARROW:
+      return moz_gtk_arrow_paint(cr, rect, state, (GtkArrowType)flags,
+                                 direction);
+    case MOZ_GTK_SPLITTER_HORIZONTAL:
+      return moz_gtk_vpaned_paint(cr, rect, state);
+    case MOZ_GTK_SPLITTER_VERTICAL:
+      return moz_gtk_hpaned_paint(cr, rect, state);
+    case MOZ_GTK_WINDOW_DECORATION:
+      return moz_gtk_window_decoration_paint(cr, rect, state, direction);
+    case MOZ_GTK_HEADER_BAR:
+    case MOZ_GTK_HEADER_BAR_MAXIMIZED:
+      return moz_gtk_header_bar_paint(widget, cr, rect, state);
+    default:
+      g_warning("Unknown widget type: %d", widget);
+  }
+
+  return MOZ_GTK_UNKNOWN_WIDGET;
+}
+
+gint moz_gtk_shutdown() {
+  /* This will destroy all of our widgets */
+  ResetWidgetCache();
+
+  return MOZ_GTK_SUCCESS;
+}