www/firefox: gracefully handle errors from Gtk font settings

PR:		1400817
Obtained from:	upstream (Firefox 57)
MFH:		2017Q4

2 files changed, 797 insertions, 1 deletions

diff --git a/www/firefox/Makefile b/www/firefox/Makefile
index c5227eb47606..23bdc2bbb0be 100644
--- a/www/firefox/Makefile
+++ b/www/firefox/Makefile
@@ -4,7 +4,7 @@
 PORTNAME=	firefox
 DISTVERSION=	56.0.2
 DISTVERSIONSUFFIX=.source
-PORTREVISION=	6
+PORTREVISION=	7
 PORTEPOCH=	1
 CATEGORIES=	www ipv6
 MASTER_SITES=	MOZILLA/${PORTNAME}/releases/${DISTVERSION}/source \
diff --git a/www/firefox/files/patch-bug1384701 b/www/firefox/files/patch-bug1384701
new file mode 100644
index 000000000000..142d5430d266
--- /dev/null
+++ b/www/firefox/files/patch-bug1384701
@@ -0,0 +1,796 @@
+diff --git widget/gtk/nsLookAndFeel.cpp widget/gtk/nsLookAndFeel.cpp
+index 6bb3e27c6653..f4c35d82200a 100644
+--- widget/gtk/nsLookAndFeel.cpp
++++ widget/gtk/nsLookAndFeel.cpp
+@@ -29,11 +29,9 @@
+ 
+ #include "mozilla/gfx/2D.h"
+ 
+-#if MOZ_WIDGET_GTK != 2
+ #include <cairo-gobject.h>
+ #include "WidgetStyleCache.h"
+ #include "prenv.h"
+-#endif
+ 
+ using mozilla::LookAndFeel;
+ 
+@@ -49,9 +47,6 @@ using mozilla::LookAndFeel;
+ 
+ nsLookAndFeel::nsLookAndFeel()
+     : nsXPLookAndFeel(),
+-#if (MOZ_WIDGET_GTK == 2)
+-      mStyle(nullptr),
+-#endif
+       mDefaultFontCached(false), mButtonFontCached(false),
+       mFieldFontCached(false), mMenuFontCached(false),
+       mInitialized(false)
+@@ -66,12 +61,8 @@ nsLookAndFeel::NativeInit()
+ 
+ nsLookAndFeel::~nsLookAndFeel()
+ {
+-#if (MOZ_WIDGET_GTK == 2)
+-    g_object_unref(mStyle);
+-#endif
+ }
+ 
+-#if MOZ_WIDGET_GTK != 2
+ // Modifies color |*aDest| as if a pattern of color |aSource| was painted with
+ // CAIRO_OPERATOR_OVER to a surface with color |*aDest|.
+ static void
+@@ -228,42 +219,19 @@ GetBorderColors(GtkStyleContext* aContext,
+     *aDarkColor = GDK_RGBA_TO_NS_RGBA(darkColor);
+     return ret;
+ }
+-#endif
+ 
+ nsresult
+ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+ {
+     EnsureInit();
+ 
+-#if (MOZ_WIDGET_GTK == 3)
+     GdkRGBA gdk_color;
+-#endif
+     nsresult res = NS_OK;
+ 
+     switch (aID) {
+         // These colors don't seem to be used for anything anymore in Mozilla
+         // (except here at least TextSelectBackground and TextSelectForeground)
+         // The CSS2 colors below are used.
+-#if (MOZ_WIDGET_GTK == 2)
+-    case eColorID_WindowBackground:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->base[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_WindowForeground:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->text[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_WidgetBackground:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_WidgetForeground:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->fg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_WidgetSelectBackground:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_SELECTED]);
+-        break;
+-    case eColorID_WidgetSelectForeground:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->fg[GTK_STATE_SELECTED]);
+-        break;
+-#else
+     case eColorID_WindowBackground:
+     case eColorID_WidgetBackground:
+     case eColorID_TextBackground:
+@@ -303,35 +271,12 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+     case eColorID__moz_html_cellhighlighttext:
+         aColor = sTextSelectedText;
+         break;
+-#endif
+     case eColorID_Widget3DHighlight:
+         aColor = NS_RGB(0xa0,0xa0,0xa0);
+         break;
+     case eColorID_Widget3DShadow:
+         aColor = NS_RGB(0x40,0x40,0x40);
+         break;
+-#if (MOZ_WIDGET_GTK == 2)
+-    case eColorID_TextBackground:
+-        // not used?
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->base[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_TextForeground: 
+-        // not used?
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->text[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_TextSelectBackground:
+-    case eColorID_IMESelectedRawTextBackground:
+-    case eColorID_IMESelectedConvertedTextBackground:
+-        // still used
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->base[GTK_STATE_SELECTED]);
+-        break;
+-    case eColorID_TextSelectForeground:
+-    case eColorID_IMESelectedRawTextForeground:
+-    case eColorID_IMESelectedConvertedTextForeground:
+-        // still used
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->text[GTK_STATE_SELECTED]);
+-        break;
+-#endif
+     case eColorID_IMERawInputBackground:
+     case eColorID_IMEConvertedTextBackground:
+         aColor = NS_TRANSPARENT;
+@@ -352,53 +297,6 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+       aColor = NS_RGB(0xff, 0, 0);
+       break;
+ 
+-#if (MOZ_WIDGET_GTK == 2)
+-        // css2  http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
+-    case eColorID_activeborder:
+-        // active window border
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_activecaption:
+-        // active window caption background
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_appworkspace:
+-        // MDI background color
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_background:
+-        // desktop background
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_captiontext:
+-        // text in active window caption, size box, and scrollbar arrow box (!)
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->fg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_graytext:
+-        // disabled text in windows, menus, etc.
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->fg[GTK_STATE_INSENSITIVE]);
+-        break;
+-    case eColorID_highlight:
+-        // background of selected item
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->base[GTK_STATE_SELECTED]);
+-        break;
+-    case eColorID_highlighttext:
+-        // text of selected item
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->text[GTK_STATE_SELECTED]);
+-        break;
+-    case eColorID_inactiveborder:
+-        // inactive window border
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID_inactivecaption:
+-        // inactive window caption
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_INSENSITIVE]);
+-        break;
+-    case eColorID_inactivecaptiontext:
+-        // text in inactive window caption
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->fg[GTK_STATE_INSENSITIVE]);
+-        break;
+-#else
+         // css2  http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
+     case eColorID_activeborder: {
+         // active window border
+@@ -433,7 +331,6 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+         ReleaseStyleContext(style);
+         break;
+     }
+-#endif
+     case eColorID_infobackground:
+         // tooltip background color
+         aColor = sInfoBackground;
+@@ -452,11 +349,7 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+         break;
+     case eColorID_scrollbar:
+         // scrollbar gray area
+-#if (MOZ_WIDGET_GTK == 2)
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_ACTIVE]);
+-#else
+         aColor = sMozScrollbar;
+-#endif
+         break;
+ 
+     case eColorID_threedlightshadow:
+@@ -465,11 +358,7 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+     case eColorID_threedface:
+     case eColorID_buttonface:
+         // 3-D face color
+-#if (MOZ_WIDGET_GTK == 3)
+         aColor = sMozWindowBackground;
+-#else
+-        aColor = sButtonBackground;
+-#endif
+         break;
+ 
+     case eColorID_buttontext:
+@@ -491,56 +380,6 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+         aColor = sFrameInnerDarkBorder;
+         break;
+ 
+-#if (MOZ_WIDGET_GTK == 2)
+-    case eColorID_threeddarkshadow:
+-        // 3-D shadow outer edge color
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->black);
+-        break;
+-
+-    case eColorID_window:
+-    case eColorID_windowframe:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_NORMAL]);
+-        break;
+-
+-    case eColorID_windowtext:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->fg[GTK_STATE_NORMAL]);
+-        break;
+-
+-    case eColorID__moz_eventreerow:
+-    case eColorID__moz_field:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->base[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID__moz_fieldtext:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->text[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID__moz_dialog:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID__moz_dialogtext:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->fg[GTK_STATE_NORMAL]);
+-        break;
+-    case eColorID__moz_dragtargetzone:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_SELECTED]);
+-        break; 
+-    case eColorID__moz_buttondefault:
+-        // default button border color
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->black);
+-        break;
+-    case eColorID__moz_buttonhoverface:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->bg[GTK_STATE_PRELIGHT]);
+-        break;
+-    case eColorID__moz_buttonhovertext:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->fg[GTK_STATE_PRELIGHT]);
+-        break;
+-    case eColorID__moz_cellhighlight:
+-    case eColorID__moz_html_cellhighlight:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->base[GTK_STATE_ACTIVE]);
+-        break;
+-    case eColorID__moz_cellhighlighttext:
+-    case eColorID__moz_html_cellhighlighttext:
+-        aColor = GDK_COLOR_TO_NS_RGB(mStyle->text[GTK_STATE_ACTIVE]);
+-        break;
+-#else
+     case eColorID_threeddarkshadow:
+         // Hardcode to black
+         aColor = NS_RGB(0x00,0x00,0x00);
+@@ -574,7 +413,6 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+     case eColorID__moz_buttonhovertext:
+         aColor = sButtonHoverText;
+         break;
+-#endif
+     case eColorID__moz_menuhover:
+         aColor = sMenuHover;
+         break;
+@@ -590,11 +428,6 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+     case eColorID__moz_comboboxtext:
+         aColor = sComboBoxText;
+         break;
+-#if (MOZ_WIDGET_GTK == 2)
+-    case eColorID__moz_combobox:
+-        aColor = sComboBoxBackground;
+-        break;
+-#endif
+     case eColorID__moz_menubartext:
+         aColor = sMenuBarText;
+         break;
+@@ -602,11 +435,7 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+         aColor = sMenuBarHoverText;
+         break;
+     case eColorID__moz_gtk_info_bar_text:
+-#if (MOZ_WIDGET_GTK == 3)
+         aColor = sInfoBarText;
+-#else
+-        aColor = sInfoText;
+-#endif
+         break;
+     default:
+         /* default color is BLACK */
+@@ -618,27 +447,6 @@ nsLookAndFeel::NativeGetColor(ColorID aID, nscolor& aColor)
+     return res;
+ }
+ 
+-#if (MOZ_WIDGET_GTK == 2)
+-static void darken_gdk_color(GdkColor *src, GdkColor *dest)
+-{
+-    gdouble red;
+-    gdouble green;
+-    gdouble blue;
+-
+-    red = (gdouble) src->red / 65535.0;
+-    green = (gdouble) src->green / 65535.0;
+-    blue = (gdouble) src->blue / 65535.0;
+-
+-    red *= 0.93;
+-    green *= 0.93;
+-    blue *= 0.93;
+-
+-    dest->red = red * 65535.0;
+-    dest->green = green * 65535.0;
+-    dest->blue = blue * 65535.0;
+-}
+-#endif
+-
+ static int32_t CheckWidgetStyle(GtkWidget* aWidget, const char* aStyle, int32_t aResult) {
+     gboolean value = FALSE;
+     gtk_widget_style_get(aWidget, aStyle, &value, nullptr);
+@@ -826,14 +634,8 @@ nsLookAndFeel::GetIntImpl(IntID aID, int32_t &aResult)
+         res = NS_ERROR_NOT_IMPLEMENTED;
+         break;
+     case eIntID_TouchEnabled:
+-#if MOZ_WIDGET_GTK == 3
+         aResult = mozilla::widget::WidgetUtils::IsTouchDeviceSupportPresent();
+         break;
+-#else
+-        aResult = 0;
+-        res = NS_ERROR_NOT_IMPLEMENTED;
+-#endif
+-        break;
+     case eIntID_MacGraphiteTheme:
+         aResult = 0;
+         res = NS_ERROR_NOT_IMPLEMENTED;
+@@ -905,24 +707,20 @@ nsLookAndFeel::GetFloatImpl(FloatID aID, float &aResult)
+ }
+ 
+ static void
+-GetSystemFontInfo(GtkWidget *aWidget,
++GetSystemFontInfo(GtkStyleContext *aStyle,
+                   nsString *aFontName,
+                   gfxFontStyle *aFontStyle)
+ {
+-    GtkSettings *settings = gtk_widget_get_settings(aWidget);
+-
+     aFontStyle->style       = NS_FONT_STYLE_NORMAL;
+ 
+-    gchar *fontname;
+-    g_object_get(settings, "gtk-font-name", &fontname, nullptr);
+-
++    // As in
++    // https://git.gnome.org/browse/gtk+/tree/gtk/gtkwidget.c?h=3.22.19#n10333
+     PangoFontDescription *desc;
+-    desc = pango_font_description_from_string(fontname);
++    gtk_style_context_get(aStyle, gtk_style_context_get_state(aStyle),
++                          "font", &desc, nullptr);
+ 
+     aFontStyle->systemFont = true;
+ 
+-    g_free(fontname);
+-
+     NS_NAMED_LITERAL_STRING(quote, "\"");
+     NS_ConvertUTF8toUTF16 family(pango_font_description_get_family(desc));
+     *aFontName = quote + family + quote;
+@@ -953,96 +751,28 @@ GetSystemFontInfo(GtkWidget *aWidget,
+     pango_font_description_free(desc);
+ }
+ 
+-static void
+-GetSystemFontInfo(LookAndFeel::FontID aID,
+-                  nsString *aFontName,
+-                  gfxFontStyle *aFontStyle)
+-{
+-    if (aID == LookAndFeel::eFont_Widget) {
+-        GtkWidget *label = gtk_label_new("M");
+-        GtkWidget *parent = gtk_fixed_new();
+-        GtkWidget *window = gtk_window_new(GTK_WINDOW_POPUP);
+-
+-        gtk_container_add(GTK_CONTAINER(parent), label);
+-        gtk_container_add(GTK_CONTAINER(window), parent);
+-
+-        gtk_widget_ensure_style(label);
+-        GetSystemFontInfo(label, aFontName, aFontStyle);
+-        gtk_widget_destroy(window);  // no unref, windows are different
+-
+-    } else if (aID == LookAndFeel::eFont_Button) {
+-        GtkWidget *label = gtk_label_new("M");
+-        GtkWidget *parent = gtk_fixed_new();
+-        GtkWidget *button = gtk_button_new();
+-        GtkWidget *window = gtk_window_new(GTK_WINDOW_POPUP);
+-
+-        gtk_container_add(GTK_CONTAINER(button), label);
+-        gtk_container_add(GTK_CONTAINER(parent), button);
+-        gtk_container_add(GTK_CONTAINER(window), parent);
+-
+-        gtk_widget_ensure_style(label);
+-        GetSystemFontInfo(label, aFontName, aFontStyle);
+-        gtk_widget_destroy(window);  // no unref, windows are different
+-
+-    } else if (aID == LookAndFeel::eFont_Field) {
+-        GtkWidget *entry = gtk_entry_new();
+-        GtkWidget *parent = gtk_fixed_new();
+-        GtkWidget *window = gtk_window_new(GTK_WINDOW_POPUP);
+-
+-        gtk_container_add(GTK_CONTAINER(parent), entry);
+-        gtk_container_add(GTK_CONTAINER(window), parent);
+-
+-        gtk_widget_ensure_style(entry);
+-        GetSystemFontInfo(entry, aFontName, aFontStyle);
+-        gtk_widget_destroy(window);  // no unref, windows are different
+-
+-    } else {
+-        MOZ_ASSERT(aID == LookAndFeel::eFont_Menu, "unexpected font ID");
+-        GtkWidget *accel_label = gtk_accel_label_new("M");
+-        GtkWidget *menuitem = gtk_menu_item_new();
+-        GtkWidget *menu = gtk_menu_new();
+-        g_object_ref_sink(menu);
+-
+-        gtk_container_add(GTK_CONTAINER(menuitem), accel_label);
+-        gtk_menu_shell_append((GtkMenuShell *)GTK_MENU(menu), menuitem);
+-
+-        gtk_widget_ensure_style(accel_label);
+-        GetSystemFontInfo(accel_label, aFontName, aFontStyle);
+-        g_object_unref(menu);
+-    }
+-}
+-
+ bool
+ nsLookAndFeel::GetFontImpl(FontID aID, nsString& aFontName,
+                            gfxFontStyle& aFontStyle,
+                            float aDevPixPerCSSPixel)
+ {
+-  nsString *cachedFontName = nullptr;
+-  gfxFontStyle *cachedFontStyle = nullptr;
+-  bool *isCached = nullptr;
+-
+   switch (aID) {
+     case eFont_Menu:         // css2
+     case eFont_PullDownMenu: // css3
+-      cachedFontName = &mMenuFontName;
+-      cachedFontStyle = &mMenuFontStyle;
+-      isCached = &mMenuFontCached;
+-      aID = eFont_Menu;
+-      break;
++      aFontName = mMenuFontName;
++      aFontStyle = mMenuFontStyle;
++      return true;
+ 
+     case eFont_Field:        // css3
+     case eFont_List:         // css3
+-      cachedFontName = &mFieldFontName;
+-      cachedFontStyle = &mFieldFontStyle;
+-      isCached = &mFieldFontCached;
+-      aID = eFont_Field;
+-      break;
++      aFontName = mFieldFontName;
++      aFontStyle = mFieldFontStyle;
++      return true;
+ 
+     case eFont_Button:       // css3
+-      cachedFontName = &mButtonFontName;
+-      cachedFontStyle = &mButtonFontStyle;
+-      isCached = &mButtonFontCached;
+-      break;
++      aFontName = mButtonFontName;
++      aFontStyle = mButtonFontStyle;
++      return true;
+ 
+     case eFont_Caption:      // css2
+     case eFont_Icon:         // css2
+@@ -1057,21 +787,11 @@ nsLookAndFeel::GetFontImpl(FontID aID, nsString& aFontName,
+     case eFont_Dialog:       // css3
+     case eFont_Tooltips:     // moz
+     case eFont_Widget:       // moz
+-      cachedFontName = &mDefaultFontName;
+-      cachedFontStyle = &mDefaultFontStyle;
+-      isCached = &mDefaultFontCached;
+-      aID = eFont_Widget;
+-      break;
+-  }
+-
+-  if (!*isCached) {
+-    GetSystemFontInfo(aID, cachedFontName, cachedFontStyle);
+-    *isCached = true;
++    default:
++      aFontName = mDefaultFontName;
++      aFontStyle = mDefaultFontStyle;
++      return true;
+   }
+-
+-  aFontName = *cachedFontName;
+-  aFontStyle = *cachedFontStyle;
+-  return true;
+ }
+ 
+ void
+@@ -1087,70 +807,6 @@ nsLookAndFeel::EnsureInit()
+     // gtk does non threadsafe refcounting
+     MOZ_ASSERT(NS_IsMainThread());
+ 
+-#if (MOZ_WIDGET_GTK == 2)
+-    NS_ASSERTION(!mStyle, "already initialized");
+-    // GtkInvisibles come with a refcount that is not floating
+-    // (since their initialization code calls g_object_ref_sink) and
+-    // their destroy code releases that reference (which means they
+-    // have to be explicitly destroyed, since calling unref enough
+-    // to cause destruction would lead to *another* unref).
+-    // However, this combination means that it's actually still ok
+-    // to use the normal pattern, which is to g_object_ref_sink
+-    // after construction, and then destroy *and* unref when we're
+-    // done.  (Though we could skip the g_object_ref_sink and the
+-    // corresponding g_object_unref, but that's particular to
+-    // GtkInvisibles and GtkWindows.)
+-    GtkWidget *widget = gtk_invisible_new();
+-    g_object_ref_sink(widget); // effectively g_object_ref (see above)
+-
+-    gtk_widget_ensure_style(widget);
+-    mStyle = gtk_style_copy(gtk_widget_get_style(widget));
+-
+-    gtk_widget_destroy(widget);
+-    g_object_unref(widget);
+-        
+-    // tooltip foreground and background
+-    GtkStyle *style = gtk_rc_get_style_by_paths(gtk_settings_get_default(),
+-                                                "gtk-tooltips", "GtkWindow",
+-                                                GTK_TYPE_WINDOW);
+-    if (style) {
+-        sInfoBackground = GDK_COLOR_TO_NS_RGB(style->bg[GTK_STATE_NORMAL]);
+-        sInfoText = GDK_COLOR_TO_NS_RGB(style->fg[GTK_STATE_NORMAL]);
+-    }
+-
+-    // menu foreground & menu background
+-    GtkWidget *accel_label = gtk_accel_label_new("M");
+-    GtkWidget *menuitem = gtk_menu_item_new();
+-    GtkWidget *menu = gtk_menu_new();
+-
+-    g_object_ref_sink(menu);
+-
+-    gtk_container_add(GTK_CONTAINER(menuitem), accel_label);
+-    gtk_menu_shell_append(GTK_MENU_SHELL(menu), menuitem);
+-
+-    gtk_widget_set_style(accel_label, nullptr);
+-    gtk_widget_set_style(menu, nullptr);
+-    gtk_widget_realize(menu);
+-    gtk_widget_realize(accel_label);
+-
+-    style = gtk_widget_get_style(accel_label);
+-    if (style) {
+-        sMenuText = GDK_COLOR_TO_NS_RGB(style->fg[GTK_STATE_NORMAL]);
+-    }
+-
+-    style = gtk_widget_get_style(menu);
+-    if (style) {
+-        sMenuBackground = GDK_COLOR_TO_NS_RGB(style->bg[GTK_STATE_NORMAL]);
+-    }
+-    
+-    style = gtk_widget_get_style(menuitem);
+-    if (style) {
+-        sMenuHover = GDK_COLOR_TO_NS_RGB(style->bg[GTK_STATE_PRELIGHT]);
+-        sMenuHoverText = GDK_COLOR_TO_NS_RGB(style->fg[GTK_STATE_PRELIGHT]);
+-    }
+-
+-    g_object_unref(menu);
+-#else
+     GdkRGBA color;
+     GtkStyleContext *style;
+ 
+@@ -1195,6 +851,12 @@ nsLookAndFeel::EnsureInit()
+         }
+     }
+ 
++    // The label is not added to a parent widget, but shared for constructing
++    // different style contexts.  The node hierarchy is constructed only on
++    // the label style context.
++    GtkWidget *labelWidget = gtk_label_new("M");
++    g_object_ref_sink(labelWidget);
++
+     // Scrollbar colors
+     style = ClaimStyleContext(MOZ_GTK_SCROLLBAR_TROUGH_VERTICAL);
+     gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL, &color);
+@@ -1208,6 +870,13 @@ nsLookAndFeel::EnsureInit()
+     gtk_style_context_get_color(style, GTK_STATE_FLAG_NORMAL, &color);
+     sMozWindowText = GDK_RGBA_TO_NS_RGBA(color);
+     ReleaseStyleContext(style);
++    style = ClaimStyleContext(MOZ_GTK_WINDOW_CONTAINER);
++    {
++        GtkStyleContext* labelStyle = CreateStyleForWidget(labelWidget, style);
++        GetSystemFontInfo(labelStyle, &mDefaultFontName, &mDefaultFontStyle);
++        g_object_unref(labelStyle);
++    }
++    ReleaseStyleContext(style);
+ 
+     // tooltip foreground and background
+     style = ClaimStyleContext(MOZ_GTK_TOOLTIP);
+@@ -1224,6 +893,9 @@ nsLookAndFeel::EnsureInit()
+     {
+         GtkStyleContext* accelStyle =
+             CreateStyleForWidget(gtk_accel_label_new("M"), style);
++
++        GetSystemFontInfo(accelStyle, &mMenuFontName, &mMenuFontStyle);
++
+         gtk_style_context_get_color(accelStyle, GTK_STATE_FLAG_NORMAL, &color);
+         sMenuText = GDK_RGBA_TO_NS_RGBA(color);
+         gtk_style_context_get_color(accelStyle, GTK_STATE_FLAG_INSENSITIVE, &color);
+@@ -1243,17 +915,8 @@ nsLookAndFeel::EnsureInit()
+     gtk_style_context_get_color(style, GTK_STATE_FLAG_PRELIGHT, &color);
+     sMenuHoverText = GDK_RGBA_TO_NS_RGBA(color);
+     ReleaseStyleContext(style);
+-#endif
+ 
+-    // button styles
+     GtkWidget *parent = gtk_fixed_new();
+-    GtkWidget *button = gtk_button_new();
+-    GtkWidget *label = gtk_label_new("M");
+-#if (MOZ_WIDGET_GTK == 2)
+-    GtkWidget *combobox = gtk_combo_box_new();
+-    GtkWidget *comboboxLabel = gtk_label_new("M");
+-    gtk_container_add(GTK_CONTAINER(combobox), comboboxLabel);
+-#endif
+     GtkWidget *window = gtk_window_new(GTK_WINDOW_POPUP);
+     GtkWidget *treeView = gtk_tree_view_new();
+     GtkWidget *linkButton = gtk_link_button_new("http://example.com/");
+@@ -1262,94 +925,14 @@ nsLookAndFeel::EnsureInit()
+     GtkWidget *entry = gtk_entry_new();
+     GtkWidget *textView = gtk_text_view_new();
+ 
+-    gtk_container_add(GTK_CONTAINER(button), label);
+-    gtk_container_add(GTK_CONTAINER(parent), button);
+     gtk_container_add(GTK_CONTAINER(parent), treeView);
+     gtk_container_add(GTK_CONTAINER(parent), linkButton);
+-#if (MOZ_WIDGET_GTK == 2)
+-    gtk_container_add(GTK_CONTAINER(parent), combobox);
+-#endif
+     gtk_container_add(GTK_CONTAINER(parent), menuBar);
+     gtk_menu_shell_append(GTK_MENU_SHELL(menuBar), menuBarItem);
+     gtk_container_add(GTK_CONTAINER(window), parent);
+     gtk_container_add(GTK_CONTAINER(parent), entry);
+     gtk_container_add(GTK_CONTAINER(parent), textView);
+     
+-#if (MOZ_WIDGET_GTK == 2)
+-    gtk_widget_set_style(button, nullptr);
+-    gtk_widget_set_style(label, nullptr);
+-    gtk_widget_set_style(treeView, nullptr);
+-    gtk_widget_set_style(linkButton, nullptr);
+-    gtk_widget_set_style(combobox, nullptr);
+-    gtk_widget_set_style(comboboxLabel, nullptr);
+-    gtk_widget_set_style(menuBar, nullptr);
+-    gtk_widget_set_style(entry, nullptr);
+-
+-    gtk_widget_realize(button);
+-    gtk_widget_realize(label);
+-    gtk_widget_realize(treeView);
+-    gtk_widget_realize(linkButton);
+-    gtk_widget_realize(combobox);
+-    gtk_widget_realize(comboboxLabel);
+-    gtk_widget_realize(menuBar);
+-    gtk_widget_realize(entry);
+-
+-    style = gtk_widget_get_style(label);
+-    if (style) {
+-        sButtonText = GDK_COLOR_TO_NS_RGB(style->fg[GTK_STATE_NORMAL]);
+-    }
+-
+-    style = gtk_widget_get_style(comboboxLabel);
+-    if (style) {
+-        sComboBoxText = GDK_COLOR_TO_NS_RGB(style->fg[GTK_STATE_NORMAL]);
+-    }
+-    style = gtk_widget_get_style(combobox);
+-    if (style) {
+-        sComboBoxBackground = GDK_COLOR_TO_NS_RGB(style->bg[GTK_STATE_NORMAL]);
+-    }
+-
+-    style = gtk_widget_get_style(menuBar);
+-    if (style) {
+-        sMenuBarText = GDK_COLOR_TO_NS_RGB(style->fg[GTK_STATE_NORMAL]);
+-        sMenuBarHoverText = GDK_COLOR_TO_NS_RGB(style->fg[GTK_STATE_SELECTED]);
+-    }
+-
+-    // GTK's guide to fancy odd row background colors:
+-    // 1) Check if a theme explicitly defines an odd row color
+-    // 2) If not, check if it defines an even row color, and darken it
+-    //    slightly by a hardcoded value (gtkstyle.c)
+-    // 3) If neither are defined, take the base background color and
+-    //    darken that by a hardcoded value
+-    colorValuePtr = nullptr;
+-    gtk_widget_style_get(treeView,
+-                         "odd-row-color", &colorValuePtr,
+-                         nullptr);
+-
+-    if (colorValuePtr) {
+-        colorValue = *colorValuePtr;
+-    } else {
+-        gtk_widget_style_get(treeView,
+-                             "even-row-color", &colorValuePtr,
+-                             nullptr);
+-        if (colorValuePtr)
+-            darken_gdk_color(colorValuePtr, &colorValue);
+-        else
+-            darken_gdk_color(&treeView->style->base[GTK_STATE_NORMAL], &colorValue);
+-    }
+-
+-    sOddCellBackground = GDK_COLOR_TO_NS_RGB(colorValue);
+-    if (colorValuePtr)
+-        gdk_color_free(colorValuePtr);
+-
+-    style = gtk_widget_get_style(button);
+-    if (style) {
+-        sButtonBackground = GDK_COLOR_TO_NS_RGB(style->bg[GTK_STATE_NORMAL]);
+-        sFrameOuterLightBorder =
+-            GDK_COLOR_TO_NS_RGB(style->light[GTK_STATE_NORMAL]);
+-        sFrameInnerDarkBorder =
+-            GDK_COLOR_TO_NS_RGB(style->dark[GTK_STATE_NORMAL]);
+-    }
+-#else
+     // Text colors
+     GdkRGBA bgColor;
+     // If the text window background is translucent, then the background of
+@@ -1381,8 +964,10 @@ nsLookAndFeel::EnsureInit()
+     // Button text color
+     style = ClaimStyleContext(MOZ_GTK_BUTTON);
+     {
+-        GtkStyleContext* labelStyle =
+-            CreateStyleForWidget(gtk_label_new("M"), style);
++        GtkStyleContext* labelStyle = CreateStyleForWidget(labelWidget, style);
++
++        GetSystemFontInfo(labelStyle, &mButtonFontName, &mButtonFontStyle);
++
+         gtk_style_context_get_color(labelStyle, GTK_STATE_FLAG_NORMAL, &color);
+         sButtonText = GDK_RGBA_TO_NS_RGBA(color);
+         gtk_style_context_get_color(labelStyle, GTK_STATE_FLAG_PRELIGHT, &color);
+@@ -1446,7 +1031,6 @@ nsLookAndFeel::EnsureInit()
+     gtk_style_context_add_class(style, GTK_STYLE_CLASS_INFO);
+     gtk_style_context_get_color(style, GTK_STATE_FLAG_NORMAL, &color);
+     sInfoBarText = GDK_RGBA_TO_NS_RGBA(color);
+-#endif
+     // Some themes have a unified menu bar, and support window dragging on it
+     gboolean supports_menubar_drag = FALSE;
+     GParamSpec *param_spec =
+@@ -1493,7 +1074,11 @@ nsLookAndFeel::EnsureInit()
+                          "cursor-aspect-ratio", &sCaretRatio,
+                          nullptr);
+ 
++    GetSystemFontInfo(gtk_widget_get_style_context(entry),
++                      &mFieldFontName, &mFieldFontStyle);
++
+     gtk_widget_destroy(window);
++    g_object_unref(labelWidget);
+ }
+ 
+ // virtual
+@@ -1515,11 +1100,6 @@ nsLookAndFeel::RefreshImpl()
+     mFieldFontCached = false;
+     mMenuFontCached = false;
+ 
+-#if (MOZ_WIDGET_GTK == 2)
+-    g_object_unref(mStyle);
+-    mStyle = nullptr;
+-#endif
+-
+     mInitialized = false;
+ }
+ 
+diff --git widget/gtk/nsLookAndFeel.h widget/gtk/nsLookAndFeel.h
+index 9a4015e95415..38cd51c056d6 100644
+--- widget/gtk/nsLookAndFeel.h
++++ widget/gtk/nsLookAndFeel.h
+@@ -33,9 +33,6 @@ public:
+     virtual bool GetEchoPasswordImpl();
+ 
+ protected:
+-#if (MOZ_WIDGET_GTK == 2)
+-    struct _GtkStyle *mStyle;
+-#endif
+ 
+     // Cached fonts
+     bool mDefaultFontCached;
+@@ -63,7 +60,6 @@ protected:
+     nscolor sMenuHoverText;
+     nscolor sButtonText;
+     nscolor sButtonHoverText;
+-    nscolor sButtonBackground;
+     nscolor sFrameOuterLightBorder;
+     nscolor sFrameInnerDarkBorder;
+     nscolor sOddCellBackground;
+@@ -77,9 +73,7 @@ protected:
+     nscolor sTextSelectedText;
+     nscolor sTextSelectedBackground;
+     nscolor sMozScrollbar;
+-#if (MOZ_WIDGET_GTK == 3)
+     nscolor sInfoBarText;
+-#endif
+     char16_t sInvisibleCharacter;
+     float   sCaretRatio;
+     bool    sMenuSupportsDrag;