diff --git a/dom/ipc/ContentChild.cpp b/dom/ipc/ContentChild.cpp
index c85a50671c04..586c5199e9c5 100644
--- a/dom/ipc/ContentChild.cpp
+++ b/dom/ipc/ContentChild.cpp
@@ -4,6 +4,11 @@
  * 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/. */
 
+#ifdef MOZ_WIDGET_GTK
+#  include <gdk/gdkx.h>
+#  include <gtk/gtk.h>
+#endif
+
 #include "BrowserChild.h"
 #include "ContentChild.h"
 #include "GeckoProfiler.h"
@@ -281,9 +286,7 @@
 #include "private/pprio.h"
 
 #ifdef MOZ_WIDGET_GTK
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include "nsAppRunner.h"
-#  include <gtk/gtk.h>
 #endif
 
 #ifdef MOZ_CODE_COVERAGE
@@ -724,7 +727,8 @@ bool ContentChild::Init(MessageLoop* aIOLoop, base::ProcessId aParentPid,
 
 #ifdef MOZ_X11
 #  ifdef MOZ_WIDGET_GTK
-  if (GdkIsX11Display() && !gfxPlatform::IsHeadless()) {
+  if (GDK_IS_X11_DISPLAY(gdk_display_get_default()) &&
+      !gfxPlatform::IsHeadless()) {
     // Send the parent our X socket to act as a proxy reference for our X
     // resources.
     int xSocketFd = ConnectionNumber(DefaultXDisplay());
diff --git a/dom/plugins/base/nsPluginHost.cpp b/dom/plugins/base/nsPluginHost.cpp
index 4a54b78949ed..7b1ab80ee1dd 100644
--- a/dom/plugins/base/nsPluginHost.cpp
+++ b/dom/plugins/base/nsPluginHost.cpp
@@ -113,7 +113,8 @@
 #  include "winbase.h"
 #endif
 #if (MOZ_WIDGET_GTK)
-#  include "mozilla/WidgetUtilsGtk.h"
+#  include <gdk/gdk.h>
+#  include <gdk/gdkx.h>
 #endif
 
 using namespace mozilla;
@@ -288,8 +289,11 @@ nsPluginHost::nsPluginHost()
       Preferences::GetBool("plugin.override_internal_types", false);
 
   bool waylandBackend = false;
-#if defined(MOZ_WIDGET_GTK)
-  waylandBackend = mozilla::widget::GdkIsWaylandDisplay();
+#if defined(MOZ_WIDGET_GTK) && defined(MOZ_X11)
+  GdkDisplay* display = gdk_display_get_default();
+  if (display) {
+    waylandBackend = !GDK_IS_X11_DISPLAY(display);
+  }
 #endif
   mPluginsDisabled =
       Preferences::GetBool("plugin.disable", false) || waylandBackend;
diff --git a/dom/plugins/ipc/PluginModuleChild.cpp b/dom/plugins/ipc/PluginModuleChild.cpp
index e29b13917672..81eb8467d468 100644
--- a/dom/plugins/ipc/PluginModuleChild.cpp
+++ b/dom/plugins/ipc/PluginModuleChild.cpp
@@ -13,7 +13,6 @@
 #include "mozilla/ipc/MessageChannel.h"
 
 #ifdef MOZ_WIDGET_GTK
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include <gtk/gtk.h>
 #  include <gdk/gdkx.h>
 #endif
@@ -1552,7 +1551,7 @@ NPError PluginModuleChild::DoNP_Initialize(const PluginSettings& aSettings) {
 
 #ifdef MOZ_X11
 #  ifdef MOZ_WIDGET_GTK
-  if (!GdkIsX11Display()) {
+  if (!GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     // We don't support NPAPI plugins on Wayland.
     return NPERR_GENERIC_ERROR;
   }
diff --git a/gfx/gl/GLContextProviderEGL.cpp b/gfx/gl/GLContextProviderEGL.cpp
index 60578735c7ab..52bd92742b96 100644
--- a/gfx/gl/GLContextProviderEGL.cpp
+++ b/gfx/gl/GLContextProviderEGL.cpp
@@ -78,14 +78,32 @@
 
 #if defined(MOZ_WIDGET_GTK)
 #  include "mozilla/widget/GtkCompositorWidget.h"
-#  include "mozilla/WidgetUtilsGtk.h"
 #  if defined(MOZ_WAYLAND)
+#    include <dlfcn.h>
 #    include <gdk/gdkwayland.h>
 #    include <wayland-egl.h>
 #    define MOZ_GTK_WAYLAND 1
 #  endif
 #endif
 
+inline bool IsWaylandDisplay() {
+#ifdef MOZ_GTK_WAYLAND
+  return gdk_display_get_default() &&
+         GDK_IS_WAYLAND_DISPLAY(gdk_display_get_default());
+#else
+  return false;
+#endif
+}
+
+inline bool IsX11Display() {
+#ifdef MOZ_WIDGET_GTK
+  return gdk_display_get_default() &&
+         GDK_IS_X11_DISPLAY(gdk_display_get_default());
+#else
+  return false;
+#endif
+}
+
 struct wl_egl_window;
 
 using namespace mozilla::gfx;
@@ -110,17 +128,15 @@ class WaylandGLSurface {
 static nsDataHashtable<nsPtrHashKey<void>, WaylandGLSurface*> sWaylandGLSurface;
 
 void DeleteWaylandGLSurface(EGLSurface surface) {
-#  ifdef MOZ_GTK_WAYLAND
   // We're running on Wayland which means our EGLSurface may
   // have attached Wayland backend data which must be released.
-  if (GdkIsWaylandDisplay()) {
+  if (IsWaylandDisplay()) {
     auto entry = sWaylandGLSurface.Lookup(surface);
     if (entry) {
       delete entry.Data();
       entry.Remove();
     }
   }
-#  endif
 }
 #endif
 
@@ -253,10 +269,10 @@ already_AddRefed<GLContext> GLContextEGLFactory::CreateImpl(
   }
 
   int visualID = 0;
+  if (IsX11Display()) {
 #ifdef MOZ_X11
-  GdkDisplay* gdkDisplay = gdk_display_get_default();
-  if (GdkIsX11Display(gdkDisplay)) {
-    auto* display = GDK_DISPLAY_XDISPLAY(gdkDisplay);
+    GdkDisplay* gdkDisplay = gdk_display_get_default();
+    auto display = gdkDisplay ? GDK_DISPLAY_XDISPLAY(gdkDisplay) : nullptr;
     if (display) {
       XWindowAttributes windowAttrs;
       if (!XGetWindowAttributes(display, (Window)aWindow, &windowAttrs)) {
@@ -265,8 +281,8 @@ already_AddRefed<GLContext> GLContextEGLFactory::CreateImpl(
       }
       visualID = XVisualIDFromVisual(windowAttrs.visual);
     }
-  }
 #endif
+  }
 
   bool doubleBuffered = true;
 
@@ -330,12 +346,10 @@ already_AddRefed<GLContext> GLContextEGLFactory::CreateImpl(
   gl->MakeCurrent();
   gl->SetIsDoubleBuffered(doubleBuffered);
 
-#ifdef MOZ_GTK_WAYLAND
-  if (surface && GdkIsWaylandDisplay()) {
+  if (surface && IsWaylandDisplay()) {
     // Make eglSwapBuffers() non-blocking on wayland
     egl->fSwapInterval(0);
   }
-#endif
   if (aWebRender && egl->mLib->IsANGLE()) {
     MOZ_ASSERT(doubleBuffered);
     egl->fSwapInterval(0);
@@ -515,12 +529,10 @@ bool GLContextEGL::RenewSurface(CompositorWidget* aWidget) {
   }
   const bool ok = MakeCurrent(true);
   MOZ_ASSERT(ok);
-#ifdef MOZ_GTK_WAYLAND
-  if (mSurface && GdkIsWaylandDisplay()) {
+  if (mSurface && IsWaylandDisplay()) {
     // Make eglSwapBuffers() non-blocking on wayland
     mEgl->fSwapInterval(0);
   }
-#endif
   return ok;
 }
 
@@ -1043,14 +1055,11 @@ EGLSurface GLContextEGL::CreateCompatibleSurface(void* aWindow) const {
 
 static void FillContextAttribs(bool es3, bool useGles, nsTArray<EGLint>* out) {
   out->AppendElement(LOCAL_EGL_SURFACE_TYPE);
-#ifdef MOZ_GTK_WAYLAND
-  if (GdkIsWaylandDisplay()) {
+  if (IsWaylandDisplay()) {
     // Wayland on desktop does not support PBuffer or FBO.
     // We create a dummy wl_egl_window instead.
     out->AppendElement(LOCAL_EGL_WINDOW_BIT);
-  } else
-#endif
-  {
+  } else {
     out->AppendElement(LOCAL_EGL_PBUFFER_BIT);
   }
 
@@ -1166,12 +1175,9 @@ RefPtr<GLContextEGL> GLContextEGL::CreateEGLPBufferOffscreenContextImpl(
 
   mozilla::gfx::IntSize pbSize(size);
   EGLSurface surface = nullptr;
-#ifdef MOZ_GTK_WAYLAND
-  if (GdkIsWaylandDisplay()) {
+  if (IsWaylandDisplay()) {
     surface = GLContextEGL::CreateWaylandBufferSurface(*egl, config, pbSize);
-  } else
-#endif
-  {
+  } else {
     surface = GLContextEGL::CreatePBufferSurfaceTryingPowerOfTwo(
         *egl, config, LOCAL_EGL_NONE, pbSize);
   }
diff --git a/gfx/gl/GLContextProviderWayland.cpp b/gfx/gl/GLContextProviderWayland.cpp
index 26982106bcc6..4f7c15380c27 100644
--- a/gfx/gl/GLContextProviderWayland.cpp
+++ b/gfx/gl/GLContextProviderWayland.cpp
@@ -4,7 +4,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifdef MOZ_WIDGET_GTK
-#  include "mozilla/WidgetUtilsGtk.h"
+#  include <gdk/gdk.h>
+#  include <gdk/gdkx.h>
 #endif
 
 #include "GLContextProvider.h"
@@ -20,7 +21,7 @@ static class GLContextProviderEGL sGLContextProviderEGL;
 already_AddRefed<GLContext> GLContextProviderWayland::CreateForCompositorWidget(
     CompositorWidget* aCompositorWidget, bool aWebRender,
     bool aForceAccelerated) {
-  if (GdkIsX11Display()) {
+  if (GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     return sGLContextProviderX11.CreateForCompositorWidget(
         aCompositorWidget, aWebRender, aForceAccelerated);
   } else {
@@ -32,7 +33,7 @@ already_AddRefed<GLContext> GLContextProviderWayland::CreateForCompositorWidget(
 /*static*/
 already_AddRefed<GLContext> GLContextProviderWayland::CreateHeadless(
     const GLContextCreateDesc& desc, nsACString* const out_failureId) {
-  if (GdkIsX11Display()) {
+  if (GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     return sGLContextProviderX11.CreateHeadless(desc, out_failureId);
   } else {
     return sGLContextProviderEGL.CreateHeadless(desc, out_failureId);
@@ -41,7 +42,7 @@ already_AddRefed<GLContext> GLContextProviderWayland::CreateHeadless(
 
 /*static*/
 GLContext* GLContextProviderWayland::GetGlobalContext() {
-  if (GdkIsX11Display()) {
+  if (GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     return sGLContextProviderX11.GetGlobalContext();
   } else {
     return sGLContextProviderEGL.GetGlobalContext();
@@ -50,7 +51,7 @@ GLContext* GLContextProviderWayland::GetGlobalContext() {
 
 /*static*/
 void GLContextProviderWayland::Shutdown() {
-  if (GdkIsX11Display()) {
+  if (GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     sGLContextProviderX11.Shutdown();
   } else {
     sGLContextProviderEGL.Shutdown();
diff --git a/gfx/gl/GLLibraryEGL.cpp b/gfx/gl/GLLibraryEGL.cpp
index a385ef58bb97..02c93f8381c9 100644
--- a/gfx/gl/GLLibraryEGL.cpp
+++ b/gfx/gl/GLLibraryEGL.cpp
@@ -37,12 +37,13 @@
 #include "GLReadTexImageHelper.h"
 #include "ScopedGLHelpers.h"
 #ifdef MOZ_WIDGET_GTK
-#  include "mozilla/WidgetUtilsGtk.h"
+#  include <gdk/gdk.h>
 #  ifdef MOZ_WAYLAND
+#    include <gdk/gdkwayland.h>
+#    include <dlfcn.h>
 #    include "mozilla/widget/nsWaylandDisplay.h"
 #  endif  // MOZ_WIDGET_GTK
-#  include <gdk/gdk.h>
-#endif  // MOZ_WAYLAND
+#endif    // MOZ_WAYLAND
 
 namespace mozilla {
 namespace gl {
@@ -783,7 +784,7 @@ std::shared_ptr<EglDisplay> GLLibraryEGL::CreateDisplay(
 #ifdef MOZ_WAYLAND
     // Some drivers doesn't support EGL_DEFAULT_DISPLAY
     GdkDisplay* gdkDisplay = gdk_display_get_default();
-    if (widget::GdkIsWaylandDisplay(gdkDisplay)) {
+    if (gdkDisplay && !GDK_IS_X11_DISPLAY(gdkDisplay)) {
       nativeDisplay = widget::WaylandDisplayGetWLDisplay(gdkDisplay);
       if (!nativeDisplay) {
         NS_WARNING("Failed to get wl_display.");
diff --git a/gfx/src/X11Util.h b/gfx/src/X11Util.h
index cfa86bec5b0b..fc583fb6d420 100644
--- a/gfx/src/X11Util.h
+++ b/gfx/src/X11Util.h
@@ -12,7 +12,6 @@
 #if defined(MOZ_WIDGET_GTK)
 #  include <gdk/gdk.h>
 #  include <gdk/gdkx.h>
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include "X11UndefineNone.h"
 #else
 #  error Unknown toolkit
@@ -29,7 +28,7 @@ namespace mozilla {
 inline Display* DefaultXDisplay() {
 #if defined(MOZ_WIDGET_GTK)
   GdkDisplay* gdkDisplay = gdk_display_get_default();
-  if (mozilla::widget::GdkIsX11Display(gdkDisplay)) {
+  if (GDK_IS_X11_DISPLAY(gdkDisplay)) {
     return GDK_DISPLAY_XDISPLAY(gdkDisplay);
   }
 #endif
diff --git a/gfx/thebes/gfxFcPlatformFontList.cpp b/gfx/thebes/gfxFcPlatformFontList.cpp
index c6feec8642ce..b647a619ac9a 100644
--- a/gfx/thebes/gfxFcPlatformFontList.cpp
+++ b/gfx/thebes/gfxFcPlatformFontList.cpp
@@ -39,7 +39,6 @@
 #ifdef MOZ_WIDGET_GTK
 #  include <gdk/gdk.h>
 #  include "gfxPlatformGtk.h"
-#  include "mozilla/WidgetUtilsGtk.h"
 #endif
 
 #ifdef MOZ_X11
@@ -717,7 +716,7 @@ static void PreparePattern(FcPattern* aPattern, bool aIsPrinterFont) {
     int lcdfilter;
     if (FcPatternGet(aPattern, FC_LCD_FILTER, 0, &value) == FcResultNoMatch) {
       GdkDisplay* dpy = gdk_display_get_default();
-      if (mozilla::widget::GdkIsX11Display(dpy) &&
+      if (GDK_IS_X11_DISPLAY(dpy) &&
           GetXftInt(GDK_DISPLAY_XDISPLAY(dpy), "lcdfilter", &lcdfilter)) {
         FcPatternAddInteger(aPattern, FC_LCD_FILTER, lcdfilter);
       }
diff --git a/gfx/thebes/gfxPlatformGtk.cpp b/gfx/thebes/gfxPlatformGtk.cpp
index 86d0e979d8a9..93ada3d9f996 100644
--- a/gfx/thebes/gfxPlatformGtk.cpp
+++ b/gfx/thebes/gfxPlatformGtk.cpp
@@ -97,7 +97,9 @@ gfxPlatformGtk::gfxPlatformGtk() {
   }
 
   mMaxGenericSubstitutions = UNINITIALIZED_VALUE;
-  mIsX11Display = gfxPlatform::IsHeadless() ? false : GdkIsX11Display();
+  mIsX11Display = gfxPlatform::IsHeadless()
+                      ? false
+                      : GDK_IS_X11_DISPLAY(gdk_display_get_default());
   if (XRE_IsParentProcess()) {
 #ifdef MOZ_X11
     if (mIsX11Display && mozilla::Preferences::GetBool("gfx.xrender.enabled")) {
diff --git a/gfx/webrender_bindings/RenderCompositorEGL.cpp b/gfx/webrender_bindings/RenderCompositorEGL.cpp
index b35b30929830..9bc88bde148b 100644
--- a/gfx/webrender_bindings/RenderCompositorEGL.cpp
+++ b/gfx/webrender_bindings/RenderCompositorEGL.cpp
@@ -18,8 +18,9 @@
 #include "mozilla/widget/CompositorWidget.h"
 
 #ifdef MOZ_WAYLAND
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include "mozilla/widget/GtkCompositorWidget.h"
+#  include <gdk/gdk.h>
+#  include <gdk/gdkx.h>
 #endif
 
 #ifdef MOZ_WIDGET_ANDROID
@@ -36,7 +37,8 @@ namespace mozilla::wr {
 UniquePtr<RenderCompositor> RenderCompositorEGL::Create(
     RefPtr<widget::CompositorWidget> aWidget, nsACString& aError) {
 #ifdef MOZ_WAYLAND
-  if (!mozilla::widget::GdkIsWaylandDisplay()) {
+  if (!gdk_display_get_default() ||
+      GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     return nullptr;
   }
 #endif
diff --git a/gfx/webrender_bindings/RenderThread.cpp b/gfx/webrender_bindings/RenderThread.cpp
index 4f031f27adbb..a59d648ff920 100644
--- a/gfx/webrender_bindings/RenderThread.cpp
+++ b/gfx/webrender_bindings/RenderThread.cpp
@@ -41,7 +41,7 @@
 #endif
 
 #ifdef MOZ_WIDGET_GTK
-#  include "mozilla/WidgetUtilsGtk.h"
+#  include <gdk/gdkx.h>
 #endif
 
 #ifdef MOZ_WAYLAND
@@ -1125,7 +1125,8 @@ static already_AddRefed<gl::GLContext> CreateGLContext(nsACString& aError) {
 #elif defined(MOZ_WIDGET_ANDROID)
   gl = CreateGLContextEGL();
 #elif defined(MOZ_WAYLAND)
-  if (mozilla::widget::GdkIsWaylandDisplay()) {
+  if (gdk_display_get_default() &&
+      !GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     gl = CreateGLContextEGL();
   }
 #elif XP_MACOSX
diff --git a/layout/xul/nsMenuPopupFrame.cpp b/layout/xul/nsMenuPopupFrame.cpp
index da1b56fdae35..192113d37c40 100644
--- a/layout/xul/nsMenuPopupFrame.cpp
+++ b/layout/xul/nsMenuPopupFrame.cpp
@@ -58,7 +58,9 @@
 #include "mozilla/dom/KeyboardEventBinding.h"
 #include <algorithm>
 #ifdef MOZ_WAYLAND
-#  include "mozilla/WidgetUtilsGtk.h"
+#  include <gdk/gdk.h>
+#  include <gdk/gdkx.h>
+#  include <gdk/gdkwayland.h>
 #endif /* MOZ_WAYLAND */
 
 #include "X11UndefineNone.h"
@@ -544,7 +546,8 @@ void nsMenuPopupFrame::LayoutPopup(nsBoxLayoutState& aState,
   prefSize = XULBoundsCheck(minSize, prefSize, maxSize);
 
 #ifdef MOZ_WAYLAND
-  static bool inWayland = mozilla::widget::GdkIsWaylandDisplay();
+  static bool inWayland = gdk_display_get_default() &&
+                          !GDK_IS_X11_DISPLAY(gdk_display_get_default());
 #else
   static bool inWayland = false;
 #endif
@@ -1447,7 +1450,8 @@ nsresult nsMenuPopupFrame::SetPopupPosition(nsIFrame* aAnchorFrame,
       // the popup's margin.
 
 #ifdef MOZ_WAYLAND
-      if (mozilla::widget::GdkIsWaylandDisplay()) {
+      if (gdk_display_get_default() &&
+          !GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
         screenPoint = nsPoint(anchorRect.x, anchorRect.y);
         mAnchorRect = anchorRect;
       }
@@ -1584,7 +1588,8 @@ nsresult nsMenuPopupFrame::SetPopupPosition(nsIFrame* aAnchorFrame,
       // because we don't know the absolute position of the window on the
       // screen.
 #ifdef MOZ_WAYLAND
-    static bool inWayland = mozilla::widget::GdkIsWaylandDisplay();
+    static bool inWayland = gdk_display_get_default() &&
+                            !GDK_IS_X11_DISPLAY(gdk_display_get_default());
 #else
     static bool inWayland = false;
 #endif
@@ -1724,7 +1729,8 @@ LayoutDeviceIntRect nsMenuPopupFrame::GetConstraintRect(
   nsCOMPtr<nsIScreenManager> sm(
       do_GetService("@mozilla.org/gfx/screenmanager;1"));
 #ifdef MOZ_WAYLAND
-  static bool inWayland = mozilla::widget::GdkIsWaylandDisplay();
+  static bool inWayland = gdk_display_get_default() &&
+                          !GDK_IS_X11_DISPLAY(gdk_display_get_default());
 #else
   static bool inWayland = false;
 #endif
diff --git a/security/sandbox/linux/broker/SandboxBrokerPolicyFactory.cpp b/security/sandbox/linux/broker/SandboxBrokerPolicyFactory.cpp
index a43b39ff0be0..3083ebc4a129 100644
--- a/security/sandbox/linux/broker/SandboxBrokerPolicyFactory.cpp
+++ b/security/sandbox/linux/broker/SandboxBrokerPolicyFactory.cpp
@@ -37,8 +37,11 @@
 #endif
 
 #ifdef MOZ_WIDGET_GTK
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include <glib.h>
+#  ifdef MOZ_WAYLAND
+#    include <gdk/gdk.h>
+#    include <gdk/gdkx.h>
+#  endif
 #endif
 
 #include <dirent.h>
@@ -504,9 +507,13 @@ void SandboxBrokerPolicyFactory::InitContentPolicy() {
 #if defined(MOZ_WIDGET_GTK) && defined(MOZ_X11)
     // Allow local X11 connections, for Primus and VirtualGL to contact
     // the secondary X server. No exception for Wayland.
-    if (mozilla::widget::GdkIsX11Display()) {
+#  if defined(MOZ_WAYLAND)
+    if (GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
       policy->AddPrefix(SandboxBroker::MAY_CONNECT, "/tmp/.X11-unix/X");
     }
+#  else
+    policy->AddPrefix(SandboxBroker::MAY_CONNECT, "/tmp/.X11-unix/X");
+#  endif
     if (const auto xauth = PR_GetEnv("XAUTHORITY")) {
       policy->AddPath(rdonly, xauth);
     }
diff --git a/security/sandbox/linux/launch/SandboxLaunch.cpp b/security/sandbox/linux/launch/SandboxLaunch.cpp
index 1efcd3846696..6f00bd41727b 100644
--- a/security/sandbox/linux/launch/SandboxLaunch.cpp
+++ b/security/sandbox/linux/launch/SandboxLaunch.cpp
@@ -47,7 +47,6 @@
 #  ifndef MOZ_WIDGET_GTK
 #    error "Unknown toolkit"
 #  endif
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include <gdk/gdk.h>
 #  include <gdk/gdkx.h>
 #  include "X11UndefineNone.h"
@@ -77,7 +76,7 @@ static bool IsDisplayLocal() {
   if (NS_WARN_IF(display == nullptr)) {
     return false;
   }
-  if (mozilla::widget::GdkIsX11Display(display)) {
+  if (GDK_IS_X11_DISPLAY(display)) {
     const int xSocketFd = ConnectionNumber(GDK_DISPLAY_XDISPLAY(display));
     if (NS_WARN_IF(xSocketFd < 0)) {
       return false;
diff --git a/toolkit/components/remote/nsRemoteService.cpp b/toolkit/components/remote/nsRemoteService.cpp
index 289fa506f4b2..7da905a4112a 100644
--- a/toolkit/components/remote/nsRemoteService.cpp
+++ b/toolkit/components/remote/nsRemoteService.cpp
@@ -11,7 +11,6 @@
 #endif
 
 #ifdef MOZ_WIDGET_GTK
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include "nsGTKRemoteServer.h"
 #  include "nsXRemoteClient.h"
 #  ifdef MOZ_ENABLE_DBUS
@@ -104,7 +103,7 @@ RemoteResult nsRemoteService::StartClient(const char* aDesktopStartupID) {
   UniquePtr<nsRemoteClient> client;
 
 #ifdef MOZ_WIDGET_GTK
-  bool useX11Remote = mozilla::widget::GdkIsX11Display();
+  bool useX11Remote = GDK_IS_X11_DISPLAY(gdk_display_get_default());
 
 #  if defined(MOZ_ENABLE_DBUS)
   if (!useX11Remote || getenv(DBUS_REMOTE_ENV)) {
@@ -153,7 +152,7 @@ void nsRemoteService::StartupServer() {
   }
 
 #ifdef MOZ_WIDGET_GTK
-  bool useX11Remote = mozilla::widget::GdkIsX11Display();
+  bool useX11Remote = GDK_IS_X11_DISPLAY(gdk_display_get_default());
 
 #  if defined(MOZ_ENABLE_DBUS)
   if (!useX11Remote || getenv(DBUS_REMOTE_ENV)) {
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index f57ac38333cd..acbc52ffcc9e 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -303,7 +303,6 @@ nsString gProcessStartupShortcut;
 #endif
 
 #if defined(MOZ_WIDGET_GTK)
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include <glib.h>
 #  if defined(DEBUG) || defined(NS_BUILD_REFCNT_LOGGING)
 #    define CLEANUP_MEMORY 1
@@ -4462,11 +4461,11 @@ int XREMain::XRE_mainStartup(bool* aExitFlag) {
       gdk_display_manager_set_default_display(gdk_display_manager_get(),
                                               mGdkDisplay);
       if (saveDisplayArg) {
-        if (GdkIsX11Display(mGdkDisplay)) {
+        if (GDK_IS_X11_DISPLAY(mGdkDisplay)) {
           SaveWordToEnv("DISPLAY", nsDependentCString(display_name));
         }
 #  ifdef MOZ_WAYLAND
-        else if (GdkIsWaylandDisplay(mGdkDisplay)) {
+        else if (!GDK_IS_X11_DISPLAY(mGdkDisplay)) {
           SaveWordToEnv("WAYLAND_DISPLAY", nsDependentCString(display_name));
         }
 #  endif
diff --git a/widget/GfxInfoX11.cpp b/widget/GfxInfoX11.cpp
index 5fc96d592b8d..7ef60878ad60 100644
--- a/widget/GfxInfoX11.cpp
+++ b/widget/GfxInfoX11.cpp
@@ -26,7 +26,6 @@
 
 #include <gdk/gdkx.h>
 #ifdef MOZ_WAYLAND
-#  include "mozilla/WidgetUtilsGtk.h"
 #  include "mozilla/widget/nsWaylandDisplay.h"
 #  include "mozilla/widget/DMABufLibWrapper.h"
 #endif
@@ -460,7 +459,8 @@ void GfxInfo::GetData() {
 
   mAdapterDescription.Assign(glRenderer);
 #ifdef MOZ_WAYLAND
-  mIsWayland = GdkIsWaylandDisplay();
+  mIsWayland = gdk_display_get_default() &&
+               !GDK_IS_X11_DISPLAY(gdk_display_get_default());
 #endif
 
   // Make a best effort guess at whether or not we are using the XWayland compat
diff --git a/widget/ScreenManager.cpp b/widget/ScreenManager.cpp
index 7c8bab31c3af..90324ebca47b 100644
--- a/widget/ScreenManager.cpp
+++ b/widget/ScreenManager.cpp
@@ -12,7 +12,9 @@
 #include "mozilla/Logging.h"
 #include "mozilla/StaticPtr.h"
 #ifdef MOZ_WAYLAND
-#  include "mozilla/WidgetUtilsGtk.h"
+#  include <gdk/gdk.h>
+#  include <gdk/gdkx.h>
+#  include <gdk/gdkwayland.h>
 #endif /* MOZ_WAYLAND */
 
 static mozilla::LazyLogModule sScreenLog("WidgetScreen");
@@ -107,7 +109,8 @@ NS_IMETHODIMP
 ScreenManager::ScreenForRect(int32_t aX, int32_t aY, int32_t aWidth,
                              int32_t aHeight, nsIScreen** aOutScreen) {
 #if defined(MOZ_WAYLAND) && defined(MOZ_LOGGING)
-  static bool inWayland = mozilla::widget::GdkIsWaylandDisplay();
+  static bool inWayland = gdk_display_get_default() &&
+                          !GDK_IS_X11_DISPLAY(gdk_display_get_default());
   if (inWayland) {
     MOZ_LOG(sScreenLog, LogLevel::Warning,
             ("Getting screen in wayland, primary display will be returned."));
diff --git a/widget/gtk/DMABufLibWrapper.cpp b/widget/gtk/DMABufLibWrapper.cpp
index 95e8e52d0224..fff0c4f54a91 100644
--- a/widget/gtk/DMABufLibWrapper.cpp
+++ b/widget/gtk/DMABufLibWrapper.cpp
@@ -10,7 +10,9 @@
 #include "mozilla/StaticPrefs_widget.h"
 #include "mozilla/StaticPrefs_media.h"
 #include "mozilla/gfx/gfxVars.h"
-#include "WidgetUtilsGtk.h"
+
+#include <gdk/gdk.h>
+#include <gdk/gdkx.h>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -169,7 +171,8 @@ nsDMABufDevice::nsDMABufDevice()
       mARGBFormat({true, true, GBM_FORMAT_ARGB8888, nullptr, 0}),
       mGbmDevice(nullptr),
       mGbmFd(-1) {
-  if (GdkIsWaylandDisplay()) {
+  if (gdk_display_get_default() &&
+      !GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     wl_display* display = WaylandDisplayGetWLDisplay();
     mRegistry = (void*)wl_display_get_registry(display);
     wl_registry_add_listener((wl_registry*)mRegistry, &registry_listener, this);
diff --git a/widget/gtk/ScreenHelperGTK.cpp b/widget/gtk/ScreenHelperGTK.cpp
index 52f0100ce8fe..67410b25a1fb 100644
--- a/widget/gtk/ScreenHelperGTK.cpp
+++ b/widget/gtk/ScreenHelperGTK.cpp
@@ -18,7 +18,6 @@
 #include "gfxPlatformGtk.h"
 #include "mozilla/dom/DOMTypes.h"
 #include "mozilla/Logging.h"
-#include "mozilla/WidgetUtilsGtk.h"
 #include "nsGtkUtils.h"
 #include "nsTArray.h"
 
@@ -94,7 +93,7 @@ ScreenHelperGTK::ScreenHelperGTK()
                          G_CALLBACK(screen_resolution_changed), this);
 #ifdef MOZ_X11
   gdk_window_add_filter(mRootWindow, root_window_event_filter, this);
-  if (GdkIsX11Display()) {
+  if (GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     mNetWorkareaAtom = XInternAtom(GDK_WINDOW_XDISPLAY(mRootWindow),
                                    "_NET_WORKAREA", X11False);
   }
@@ -151,7 +150,8 @@ static already_AddRefed<Screen> MakeScreen(GdkScreen* aScreen,
   // Use per-monitor scaling factor in gtk/wayland, or 1.0 otherwise.
   DesktopToLayoutDeviceScale contentsScale(1.0);
 #ifdef MOZ_WAYLAND
-  if (GdkIsWaylandDisplay()) {
+  GdkDisplay* gdkDisplay = gdk_display_get_default();
+  if (!GDK_IS_X11_DISPLAY(gdkDisplay)) {
     contentsScale.scale = gdkScaleFactor;
   }
 #endif
diff --git a/widget/gtk/WakeLockListener.cpp b/widget/gtk/WakeLockListener.cpp
index c14cf6b7fe5e..df76a69e4bbf 100644
--- a/widget/gtk/WakeLockListener.cpp
+++ b/widget/gtk/WakeLockListener.cpp
@@ -12,8 +12,6 @@
 #  include <dbus/dbus.h>
 #  include <dbus/dbus-glib-lowlevel.h>
 
-#  include "WidgetUtilsGtk.h"
-
 #  if defined(MOZ_X11)
 #    include "gfxPlatformGtk.h"
 #    include "prlink.h"
@@ -199,7 +197,7 @@ bool WakeLockTopic::CheckXScreenSaverSupport() {
   }
 
   GdkDisplay* gDisplay = gdk_display_get_default();
-  if (!GdkIsX11Display(gDisplay)) {
+  if (!gDisplay || !GDK_IS_X11_DISPLAY(gDisplay)) {
     return false;
   }
   Display* display = GDK_DISPLAY_XDISPLAY(gDisplay);
@@ -224,7 +222,7 @@ bool WakeLockTopic::InhibitXScreenSaver(bool inhibit) {
     return false;
   }
   GdkDisplay* gDisplay = gdk_display_get_default();
-  if (!GdkIsX11Display(gDisplay)) {
+  if (!gDisplay || !GDK_IS_X11_DISPLAY(gDisplay)) {
     return false;
   }
   Display* display = GDK_DISPLAY_XDISPLAY(gDisplay);
diff --git a/widget/gtk/WidgetUtilsGtk.cpp b/widget/gtk/WidgetUtilsGtk.cpp
index 66e764e26799..a0299bdf1419 100644
--- a/widget/gtk/WidgetUtilsGtk.cpp
+++ b/widget/gtk/WidgetUtilsGtk.cpp
@@ -6,7 +6,6 @@
 #include "WidgetUtilsGtk.h"
 #include "nsWindow.h"
 #include <gtk/gtk.h>
-#include <dlfcn.h>
 
 namespace mozilla {
 
@@ -48,31 +47,6 @@ bool IsMainWindowTransparent() {
   return nsWindow::IsToplevelWindowTransparent();
 }
 
-// We avoid linking gdk_*_display_get_type directly in order to avoid a runtime
-// dependency on GTK built with both backends. Other X11- and Wayland-specific
-// functions get stubbed out by libmozgtk and crash when called, but those
-// should only be called when the matching backend is already in use.
-
-bool GdkIsWaylandDisplay(GdkDisplay* display) {
-  static auto sGdkWaylandDisplayGetType =
-      (GType(*)())dlsym(RTLD_DEFAULT, "gdk_wayland_display_get_type");
-  return sGdkWaylandDisplayGetType &&
-         G_TYPE_CHECK_INSTANCE_TYPE(display, sGdkWaylandDisplayGetType());
-}
-
-bool GdkIsX11Display(GdkDisplay* display) {
-  static auto sGdkX11DisplayGetType =
-      (GType(*)())dlsym(RTLD_DEFAULT, "gdk_x11_display_get_type");
-  return sGdkX11DisplayGetType &&
-         G_TYPE_CHECK_INSTANCE_TYPE(display, sGdkX11DisplayGetType());
-}
-
-bool GdkIsWaylandDisplay() {
-  return GdkIsWaylandDisplay(gdk_display_get_default());
-}
-
-bool GdkIsX11Display() { return GdkIsX11Display(gdk_display_get_default()); }
-
 }  // namespace widget
 
 }  // namespace mozilla
diff --git a/widget/gtk/WidgetUtilsGtk.h b/widget/gtk/WidgetUtilsGtk.h
index bc3393644b52..5ede9aa52026 100644
--- a/widget/gtk/WidgetUtilsGtk.h
+++ b/widget/gtk/WidgetUtilsGtk.h
@@ -7,7 +7,6 @@
 #define WidgetUtilsGtk_h__
 
 #include <stdint.h>
-#include <gdk/gdk.h>
 
 namespace mozilla {
 namespace widget {
@@ -20,12 +19,6 @@ class WidgetUtilsGTK {
 
 bool IsMainWindowTransparent();
 
-bool GdkIsWaylandDisplay(GdkDisplay* display);
-bool GdkIsX11Display(GdkDisplay* display);
-
-bool GdkIsWaylandDisplay();
-bool GdkIsX11Display();
-
 }  // namespace widget
 
 }  // namespace mozilla
diff --git a/widget/gtk/compat/gdk/gdkx.h b/widget/gtk/compat/gdk/gdkx.h
index 7b0718f3cb9f..3d13c88b4d1c 100644
--- a/widget/gtk/compat/gdk/gdkx.h
+++ b/widget/gtk/compat/gdk/gdkx.h
@@ -33,6 +33,10 @@ static inline Window gdk_x11_window_get_xid(GdkWindow* window) {
   return (GDK_WINDOW_XWINDOW(window));
 }
 
+#ifndef GDK_IS_X11_DISPLAY
+#  define GDK_IS_X11_DISPLAY(a) (true)
+#endif
+
 #if !GTK_CHECK_VERSION(2, 24, 0)
 #  undef gdk_x11_set_sm_client_id
 static inline void gdk_x11_set_sm_client_id(const gchar* sm_client_id) {
diff --git a/widget/gtk/mozgtk/mozgtk.c b/widget/gtk/mozgtk/mozgtk.c
index 81f1c0fbc40d..0d376188a7f6 100644
--- a/widget/gtk/mozgtk/mozgtk.c
+++ b/widget/gtk/mozgtk/mozgtk.c
@@ -555,6 +555,8 @@ STUB(gdk_window_get_frame_clock)
 STUB(gdk_window_get_type)
 STUB(gdk_window_set_opaque_region)
 STUB(gdk_x11_window_get_xid)
+STUB(gdk_x11_display_get_type)
+STUB(gdk_wayland_display_get_type)
 STUB(gdk_wayland_display_get_wl_compositor)
 STUB(gdk_wayland_display_get_wl_display)
 STUB(gdk_wayland_window_get_wl_surface)
diff --git a/widget/gtk/nsClipboardX11.cpp b/widget/gtk/nsClipboardX11.cpp
index 652b2396be47..0439c2e68c41 100644
--- a/widget/gtk/nsClipboardX11.cpp
+++ b/widget/gtk/nsClipboardX11.cpp
@@ -18,7 +18,6 @@
 #include "nsStringStream.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/TimeStamp.h"
-#include "WidgetUtilsGtk.h"
 
 #include <gtk/gtk.h>
 
@@ -106,7 +105,7 @@ bool nsRetrievalContextX11::WaitForX11Content() {
 
   GdkDisplay* gdkDisplay = gdk_display_get_default();
   // gdk_display_get_default() returns null on headless
-  if (mozilla::widget::GdkIsX11Display(gdkDisplay)) {
+  if (gdkDisplay && GDK_IS_X11_DISPLAY(gdkDisplay)) {
     Display* xDisplay = GDK_DISPLAY_XDISPLAY(gdkDisplay);
     checkEventContext context;
     context.cbWidget = nullptr;
diff --git a/widget/gtk/nsGtkKeyUtils.cpp b/widget/gtk/nsGtkKeyUtils.cpp
index c8b18e43c745..67d1cea404b7 100644
--- a/widget/gtk/nsGtkKeyUtils.cpp
+++ b/widget/gtk/nsGtkKeyUtils.cpp
@@ -19,7 +19,6 @@
 #include "X11UndefineNone.h"
 #include "IMContextWrapper.h"
 #include "WidgetUtils.h"
-#include "WidgetUtilsGtk.h"
 #include "keysym2ucs.h"
 #include "nsContentUtils.h"
 #include "nsGtkUtils.h"
@@ -1762,7 +1761,7 @@ void KeymapWrapper::InitKeyEvent(WidgetKeyboardEvent& aKeyEvent,
   // key release events, the result isn't what we want.
   guint modifierState = aGdkKeyEvent->state;
   GdkDisplay* gdkDisplay = gdk_display_get_default();
-  if (aGdkKeyEvent->is_modifier && GdkIsX11Display(gdkDisplay)) {
+  if (aGdkKeyEvent->is_modifier && GDK_IS_X11_DISPLAY(gdkDisplay)) {
     Display* display = gdk_x11_display_get_xdisplay(gdkDisplay);
     if (XEventsQueued(display, QueuedAfterReading)) {
       XEvent nextEvent;
diff --git a/widget/gtk/nsUserIdleServiceGTK.cpp b/widget/gtk/nsUserIdleServiceGTK.cpp
index 884d52a6cab9..882ded8cade6 100644
--- a/widget/gtk/nsUserIdleServiceGTK.cpp
+++ b/widget/gtk/nsUserIdleServiceGTK.cpp
@@ -11,7 +11,6 @@
 #include "nsDebug.h"
 #include "prlink.h"
 #include "mozilla/Logging.h"
-#include "WidgetUtilsGtk.h"
 
 using mozilla::LogLevel;
 
@@ -31,7 +30,8 @@ static _XScreenSaverAllocInfo_fn _XSSAllocInfo = nullptr;
 static _XScreenSaverQueryInfo_fn _XSSQueryInfo = nullptr;
 
 static void Initialize() {
-  if (!mozilla::widget::GdkIsX11Display()) {
+  if (!gdk_display_get_default() ||
+      !GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     return;
   }
 
diff --git a/widget/gtk/nsWaylandDisplay.cpp b/widget/gtk/nsWaylandDisplay.cpp
index 063228cf33f8..310917a27bf2 100644
--- a/widget/gtk/nsWaylandDisplay.cpp
+++ b/widget/gtk/nsWaylandDisplay.cpp
@@ -11,7 +11,6 @@
 #include "base/task.h"          // for NewRunnableMethod, etc
 #include "mozilla/StaticMutex.h"
 #include "mozilla/StaticPrefs_widget.h"
-#include "WidgetUtilsGtk.h"
 
 namespace mozilla {
 namespace widget {
@@ -75,7 +74,7 @@ RefPtr<nsWaylandDisplay> WaylandDisplayGet(GdkDisplay* aGdkDisplay) {
 wl_display* WaylandDisplayGetWLDisplay(GdkDisplay* aGdkDisplay) {
   if (!aGdkDisplay) {
     aGdkDisplay = gdk_display_get_default();
-    if (!GdkIsWaylandDisplay(aGdkDisplay)) {
+    if (!aGdkDisplay || GDK_IS_X11_DISPLAY(aGdkDisplay)) {
       return nullptr;
     }
   }
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index 0e281c6ca1f3..b0d239a48b26 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -50,7 +50,6 @@
 #include "nsGtkKeyUtils.h"
 #include "nsGtkCursors.h"
 #include "ScreenHelperGTK.h"
-#include "WidgetUtilsGtk.h"
 
 #include <gtk/gtk.h>
 #include <gtk/gtkx.h>
@@ -2172,7 +2171,7 @@ guint32 nsWindow::GetLastUserInputTime() {
   // button and key releases.  Therefore use the most recent of
   // gdk_x11_display_get_user_time and the last time that we have seen.
   GdkDisplay* gdkDisplay = gdk_display_get_default();
-  guint32 timestamp = GdkIsX11Display(gdkDisplay)
+  guint32 timestamp = GDK_IS_X11_DISPLAY(gdkDisplay)
                           ? gdk_x11_display_get_user_time(gdkDisplay)
                           : gtk_get_current_event_time();
 
@@ -2490,7 +2489,7 @@ void* nsWindow::GetNativeData(uint32_t aDataType) {
     case NS_NATIVE_DISPLAY: {
 #ifdef MOZ_X11
       GdkDisplay* gdkDisplay = gdk_display_get_default();
-      if (GdkIsX11Display(gdkDisplay)) {
+      if (gdkDisplay && GDK_IS_X11_DISPLAY(gdkDisplay)) {
         return GDK_DISPLAY_XDISPLAY(gdkDisplay);
       }
 #endif /* MOZ_X11 */
@@ -7065,7 +7064,7 @@ static gboolean key_press_event_cb(GtkWidget* widget, GdkEventKey* event) {
 #    define KeyPress 2
 #  endif
   GdkDisplay* gdkDisplay = gtk_widget_get_display(widget);
-  if (GdkIsX11Display(gdkDisplay)) {
+  if (GDK_IS_X11_DISPLAY(gdkDisplay)) {
     Display* dpy = GDK_DISPLAY_XDISPLAY(gdkDisplay);
     while (XPending(dpy)) {
       XEvent next_event;
@@ -8174,7 +8173,7 @@ nsWindow::GtkWindowDecoration nsWindow::GetSystemGtkWindowDecoration() {
 
   // nsWindow::GetSystemGtkWindowDecoration can be called from various threads
   // so we can't use gfxPlatformGtk here.
-  if (GdkIsWaylandDisplay()) {
+  if (!GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
     sGtkWindowDecoration = GTK_DECORATION_CLIENT;
     return sGtkWindowDecoration;
   }