diff --git a/gfx/angle/checkout/include/EGL/eglplatform.h b/gfx/angle/checkout/include/EGL/eglplatform.h
index d1cae17724..505c334098 100644
--- a/gfx/angle/checkout/include/EGL/eglplatform.h
+++ b/gfx/angle/checkout/include/EGL/eglplatform.h
@@ -122,7 +122,8 @@ typedef intptr_t EGLNativeDisplayType;
 typedef intptr_t EGLNativePixmapType;
 typedef intptr_t EGLNativeWindowType;

-#elif defined(__unix__) || defined(USE_X11)
+#elif defined(__unix__)
+#if defined(USE_X11)

 /* X11 (tentative)  */
 #include <X11/Xlib.h>
@@ -131,6 +132,11 @@ typedef intptr_t EGLNativeWindowType;
 typedef Display *EGLNativeDisplayType;
 typedef Pixmap   EGLNativePixmapType;
 typedef Window   EGLNativeWindowType;
+#else
+typedef void              *EGLNativeDisplayType;
+typedef khronos_uintptr_t  EGLNativePixmapType;
+typedef khronos_uintptr_t  EGLNativeWindowType;
+#endif

 #elif defined(__APPLE__)

diff --git a/gfx/gl/GLContextProvider.h b/gfx/gl/GLContextProvider.h
index 12d1a497b9..bec4cd17f0 100644
--- a/gfx/gl/GLContextProvider.h
+++ b/gfx/gl/GLContextProvider.h
@@ -55,17 +55,17 @@ namespace gl {
 #  define GL_CONTEXT_PROVIDER_NAME GLContextProviderX11
 #  include "GLContextProviderImpl.h"
 #  undef GL_CONTEXT_PROVIDER_NAME
-#  if defined(MOZ_WAYLAND)
-#    define GL_CONTEXT_PROVIDER_NAME GLContextProviderWayland
-#    include "GLContextProviderImpl.h"
-#    undef GL_CONTEXT_PROVIDER_NAME
-#    define GL_CONTEXT_PROVIDER_DEFAULT GLContextProviderWayland
-#  endif
 #  ifndef GL_CONTEXT_PROVIDER_DEFAULT
 #    define GL_CONTEXT_PROVIDER_DEFAULT GLContextProviderX11
 #  endif
 #endif

+#if defined(MOZ_WAYLAND)
+#  define GL_CONTEXT_PROVIDER_NAME GLContextProviderWayland
+#  include "GLContextProviderImpl.h"
+#  undef GL_CONTEXT_PROVIDER_NAME
+#  define GL_CONTEXT_PROVIDER_DEFAULT GLContextProviderWayland
+#endif
 #ifndef GL_CONTEXT_PROVIDER_DEFAULT
 #  define GL_CONTEXT_PROVIDER_DEFAULT GLContextProviderEGL
 #endif
diff --git a/gfx/gl/GLContextProviderWayland.cpp b/gfx/gl/GLContextProviderWayland.cpp
index 3f1f926cd9..6b61708be9 100644
--- a/gfx/gl/GLContextProviderWayland.cpp
+++ b/gfx/gl/GLContextProviderWayland.cpp
@@ -14,7 +14,9 @@ namespace mozilla::gl {
 using namespace mozilla::gfx;
 using namespace mozilla::widget;

+#ifdef MOZ_X11
 static class GLContextProviderX11 sGLContextProviderX11;
+#endif
 static class GLContextProviderEGL sGLContextProviderEGL;

 // Note that if there is no GTK display, `GdkIsX11Display` and
@@ -33,9 +35,11 @@ already_AddRefed<GLContext> GLContextProviderWayland::CreateForCompositorWidget(
   if (GdkIsWaylandDisplay()) {
     return sGLContextProviderEGL.CreateForCompositorWidget(
         aCompositorWidget, aHardwareWebRender, aForceAccelerated);
+#ifdef MOZ_X11
   } else {
     return sGLContextProviderX11.CreateForCompositorWidget(
         aCompositorWidget, aHardwareWebRender, aForceAccelerated);
+#endif
   }
 }

@@ -44,8 +48,10 @@ already_AddRefed<GLContext> GLContextProviderWayland::CreateHeadless(
     const GLContextCreateDesc& desc, nsACString* const out_failureId) {
   if (GdkIsWaylandDisplay()) {
     return sGLContextProviderEGL.CreateHeadless(desc, out_failureId);
+#ifdef MOZ_X11
   } else {
     return sGLContextProviderX11.CreateHeadless(desc, out_failureId);
+#endif
   }
 }

@@ -53,8 +59,10 @@ already_AddRefed<GLContext> GLContextProviderWayland::CreateHeadless(
 GLContext* GLContextProviderWayland::GetGlobalContext() {
   if (GdkIsWaylandDisplay()) {
     return sGLContextProviderEGL.GetGlobalContext();
+#ifdef MOZ_X11
   } else {
     return sGLContextProviderX11.GetGlobalContext();
+#endif
   }
 }

@@ -62,8 +70,10 @@ GLContext* GLContextProviderWayland::GetGlobalContext() {
 void GLContextProviderWayland::Shutdown() {
   if (GdkIsWaylandDisplay()) {
     sGLContextProviderEGL.Shutdown();
+#ifdef MOZ_X11
   } else {
     sGLContextProviderX11.Shutdown();
+#endif
   }
 }

diff --git a/gfx/gl/moz.build b/gfx/gl/moz.build
index 62ad33c786..481fc6d432 100644
--- a/gfx/gl/moz.build
+++ b/gfx/gl/moz.build
@@ -13,7 +13,7 @@ elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "cocoa":
 elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "uikit":
     gl_provider = "EAGL"
 elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
-    if CONFIG["MOZ_EGL_XRENDER_COMPOSITE"]:
+    if CONFIG["MOZ_EGL_XRENDER_COMPOSITE"] or CONFIG["MOZ_WAYLAND"]:
         gl_provider = "EGL"
     else:
         gl_provider = "GLX"
diff --git a/gfx/layers/AnimationHelper.h b/gfx/layers/AnimationHelper.h
index f5a57b9c4d..72091c3a4f 100644
--- a/gfx/layers/AnimationHelper.h
+++ b/gfx/layers/AnimationHelper.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_layers_AnimationHelper_h
 #define mozilla_layers_AnimationHelper_h

+#include "X11UndefineNone.h"
 #include "mozilla/dom/Nullable.h"
 #include "mozilla/ComputedTimingFunction.h"  // for ComputedTimingFunction
 #include "mozilla/layers/AnimationStorageData.h"
@@ -15,7 +16,6 @@
 #include "mozilla/TimeStamp.h"                 // for TimeStamp
 #include "mozilla/TimingParams.h"
 #include "mozilla/Types.h"  // for SideBits
-#include "X11UndefineNone.h"
 #include <unordered_map>

 namespace mozilla {
diff --git a/gfx/layers/ipc/CompositorBridgeParent.cpp b/gfx/layers/ipc/CompositorBridgeParent.cpp
index 2ecd55b16a..82b56300c6 100644
--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -72,7 +72,7 @@
 #include "mozilla/ProfilerLabels.h"
 #include "mozilla/ProfilerMarkers.h"
 #include "mozilla/Telemetry.h"
-#ifdef MOZ_WIDGET_GTK
+#if defined(MOZ_WIDGET_GTK) && defined(MOZ_X11)
 #  include "basic/X11BasicCompositor.h"  // for X11BasicCompositor
 #endif
 #include "nsCOMPtr.h"         // for already_AddRefed
@@ -1402,7 +1402,7 @@ RefPtr<Compositor> CompositorBridgeParent::NewCompositor(
           new CompositorOGL(this, mWidget, mEGLSurfaceSize.width,
                             mEGLSurfaceSize.height, mUseExternalSurfaceSize);
     } else if (aBackendHints[i] == LayersBackend::LAYERS_BASIC) {
-#ifdef MOZ_WIDGET_GTK
+#if defined(MOZ_WIDGET_GTK) && defined(MOZ_X11)
       if (gfxVars::UseXRender()) {
         compositor = new X11BasicCompositor(this, mWidget);
       } else
diff --git a/gfx/thebes/gfxPlatformGtk.cpp b/gfx/thebes/gfxPlatformGtk.cpp
index 12e01681c7..860e876550 100644
--- a/gfx/thebes/gfxPlatformGtk.cpp
+++ b/gfx/thebes/gfxPlatformGtk.cpp
@@ -62,6 +62,9 @@
 #  include "mozilla/widget/nsWaylandDisplay.h"
 #  include "mozilla/widget/DMABufLibWrapper.h"
 #  include "mozilla/StaticPrefs_widget.h"
+#  ifdef MOZ_WIDGET_GTK
+#  include "mozilla/WidgetUtilsGtk.h"
+#  endif
 #endif

 #define GDK_PIXMAP_SIZE_MAX 32767
@@ -97,7 +97,11 @@ gfxPlatformGtk::gfxPlatformGtk() {
   }

   mMaxGenericSubstitutions = UNINITIALIZED_VALUE;
+#ifdef MOZ_X11
   mIsX11Display = gfxPlatform::IsHeadless() ? false : GdkIsX11Display();
+#else
+  mIsX11Display = 0;
+#endif
   if (XRE_IsParentProcess()) {
     InitX11EGLConfig();
     if (IsWaylandDisplay() || gfxConfig::IsEnabled(Feature::X11_EGL)) {
diff --git a/gfx/thebes/moz.build b/gfx/thebes/moz.build
index baa7005a8f..387dd29276 100644
--- a/gfx/thebes/moz.build
+++ b/gfx/thebes/moz.build
@@ -118,7 +118,6 @@ elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
     ]
     EXPORTS.mozilla.gfx += [
         "PrintTargetPDF.h",
-        "PrintTargetPS.h",
     ]
     SOURCES += [
         "gfxFcPlatformFontList.cpp",
@@ -127,13 +126,13 @@ elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
         "gfxGdkNativeRenderer.cpp",
         "gfxPlatformGtk.cpp",
         "PrintTargetPDF.cpp",
-        "PrintTargetPS.cpp",
     ]

     if CONFIG["MOZ_X11"]:
         EXPORTS += [
             "gfxXlibNativeRenderer.h",
             "gfxXlibSurface.h",
+            "PrintTargetPS.h",
         ]
         EXPORTS.mozilla.gfx += [
             "XlibDisplay.h",
@@ -142,6 +141,7 @@ elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
             "gfxXlibNativeRenderer.cpp",
             "gfxXlibSurface.cpp",
             "XlibDisplay.cpp",
+            "PrintTargetPS.cpp",
         ]

 elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "windows":
diff --git a/gfx/webrender_bindings/RenderCompositorOGLSWGL.cpp b/gfx/webrender_bindings/RenderCompositorOGLSWGL.cpp
index ec9b904967..dee437d8ae 100644
--- a/gfx/webrender_bindings/RenderCompositorOGLSWGL.cpp
+++ b/gfx/webrender_bindings/RenderCompositorOGLSWGL.cpp
@@ -27,7 +27,9 @@
 #ifdef MOZ_WIDGET_GTK
 #  include "mozilla/widget/GtkCompositorWidget.h"
 #  include <gdk/gdk.h>
-#  include <gdk/gdkx.h>
+#  ifdef MOZ_X11
+#    include <gdk/gdkx.h>
+#  endif
 #endif

 namespace mozilla {
diff --git a/toolkit/components/remote/moz.build b/toolkit/components/remote/moz.build
index 235580d6b7..b407dce197 100644
--- a/toolkit/components/remote/moz.build
+++ b/toolkit/components/remote/moz.build
@@ -13,12 +13,15 @@ SOURCES += [

 if CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
     SOURCES += [
-        "nsGTKRemoteServer.cpp",
         "nsUnixRemoteServer.cpp",
-        "nsXRemoteClient.cpp",
-        "nsXRemoteServer.cpp",
         "RemoteUtils.cpp",
     ]
+    if CONFIG["MOZ_X11"]:
+        SOURCES += [
+            "nsGTKRemoteServer.cpp",
+            "nsXRemoteClient.cpp",
+            "nsXRemoteServer.cpp",
+        ]
     if CONFIG["MOZ_ENABLE_DBUS"]:
         SOURCES += [
             "nsDBusRemoteClient.cpp",
diff --git a/toolkit/components/remote/nsRemoteService.cpp b/toolkit/components/remote/nsRemoteService.cpp
index 289fa506f4..c2fd3a1183 100644
--- a/toolkit/components/remote/nsRemoteService.cpp
+++ b/toolkit/components/remote/nsRemoteService.cpp
@@ -12,12 +12,18 @@

 #ifdef MOZ_WIDGET_GTK
 #  include "mozilla/WidgetUtilsGtk.h"
-#  include "nsGTKRemoteServer.h"
-#  include "nsXRemoteClient.h"
+#  ifdef MOZ_X11
+#    include "nsGTKRemoteServer.h"
+#    include "nsXRemoteClient.h"
+#  endif
 #  ifdef MOZ_ENABLE_DBUS
 #    include "nsDBusRemoteServer.h"
 #    include "nsDBusRemoteClient.h"
 #  endif
+#  ifdef MOZ_WAYLAND
+#    include <gdk/gdkwayland.h>
+#    include "nsRemoteClient.h"
+#  endif
 #elif defined(XP_WIN)
 #  include "nsWinRemoteServer.h"
 #  include "nsWinRemoteClient.h"
@@ -111,9 +117,11 @@ RemoteResult nsRemoteService::StartClient(const char* aDesktopStartupID) {
     client = MakeUnique<nsDBusRemoteClient>();
   }
 #  endif
+#if defined(MOZ_X11)
   if (!client && useX11Remote) {
     client = MakeUnique<nsXRemoteClient>();
   }
+#endif
 #elif defined(XP_WIN)
   client = MakeUnique<nsWinRemoteClient>();
 #elif defined(XP_DARWIN)
@@ -160,9 +168,11 @@ void nsRemoteService::StartupServer() {
     mRemoteServer = MakeUnique<nsDBusRemoteServer>();
   }
 #  endif
+#  if defined(MOZ_X11)
   if (!mRemoteServer && useX11Remote) {
     mRemoteServer = MakeUnique<nsGTKRemoteServer>();
   }
+#  endif
 #elif defined(XP_WIN)
   mRemoteServer = MakeUnique<nsWinRemoteServer>();
 #elif defined(XP_DARWIN)
diff --git a/toolkit/moz.configure b/toolkit/moz.configure
index 8bad820..2176b41 100644
--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -1170,8 +1170,6 @@ set_define("MOZ_RAW", depends_if("--enable-raw")(lambda _: True))

 # X11
 # ==============================================================
-set_config("MOZ_X11", True, when=toolkit_gtk)
-set_define("MOZ_X11", True, when=toolkit_gtk)


 @depends(webrtc, when=toolkit_gtk)
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index 3ec33c9b45..0ef2182368 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -319,6 +319,7 @@ nsString gProcessStartupShortcut;
 #  endif
 #  ifdef MOZ_X11
 #    include <gdk/gdkx.h>
+#    undef None
 #  endif /* MOZ_X11 */
 #  include <fontconfig/fontconfig.h>
 #endif
@@ -343,7 +344,6 @@ void XRE_LibFuzzerSetDriver(LibFuzzerDriver aDriver) {
 #endif  // FUZZING

 // Undo X11/X.h's definition of None
-#undef None

 namespace mozilla {
 int (*RunGTest)(int*, char**) = 0;
diff --git a/toolkit/xre/nsGDKErrorHandler.cpp b/toolkit/xre/nsGDKErrorHandler.cpp
index 421abdf12f..673a4f851b 100644
--- a/toolkit/xre/nsGDKErrorHandler.cpp
+++ b/toolkit/xre/nsGDKErrorHandler.cpp
@@ -6,14 +6,21 @@
 #include "nsGDKErrorHandler.h"

 #include <gtk/gtk.h>
+#ifdef MOZ_X11
 #include <gdk/gdkx.h>
+#endif
+#ifdef MOZ_WAYLAND
+#include <gdk/gdkwayland.h>
+#endif
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>

 #include "nsDebug.h"
 #include "nsString.h"
+#ifdef MOZ_X11
 #include "nsX11ErrorHandler.h"
+#endif

 #include "prenv.h"

@@ -26,6 +33,7 @@
  */
 static void GdkErrorHandler(const gchar* log_domain, GLogLevelFlags log_level,
                             const gchar* message, gpointer user_data) {
+#ifdef MOZ_X11
   if (strstr(message, "X Window System error")) {
     XErrorEvent event;
     nsDependentCString buffer(message);
@@ -92,10 +100,10 @@ static void GdkErrorHandler(const gchar* log_domain, GLogLevelFlags log_level,
     event.resourceid = 0;

     X11Error(event.display, &event);
-  } else {
+  }
+#endif
     g_log_default_handler(log_domain, log_level, message, user_data);
     MOZ_CRASH_UNSAFE(message);
-  }
 }

 void InstallGdkErrorHandler() {
@@ -103,7 +111,9 @@ void InstallGdkErrorHandler() {
                     (GLogLevelFlags)(G_LOG_LEVEL_ERROR | G_LOG_FLAG_FATAL |
                                      G_LOG_FLAG_RECURSION),
                     GdkErrorHandler, nullptr);
+#ifdef MOZ_X11
   if (PR_GetEnv("MOZ_X_SYNC")) {
     XSynchronize(GDK_DISPLAY_XDISPLAY(gdk_display_get_default()), X11True);
   }
+#endif
 }
diff --git a/toolkit/xre/nsNativeAppSupportUnix.cpp b/toolkit/xre/nsNativeAppSupportUnix.cpp
index e8f7b67c35..5549e40fe9 100644
--- a/toolkit/xre/nsNativeAppSupportUnix.cpp
+++ b/toolkit/xre/nsNativeAppSupportUnix.cpp
@@ -401,7 +401,6 @@ static void SetSMProperty(SmProp& prop, const char* name, const char* type,
   prop.num_vals = numVals;
   prop.vals = vals;
 }
-#endif /* MOZ_X11 */

 static void RemoveArg(char** argv) {
   do {
@@ -411,6 +410,7 @@ static void RemoveArg(char** argv) {

   --gArgc;
 }
+#endif /* MOZ_X11 */

 NS_IMETHODIMP
 nsNativeAppSupportUnix::Start(bool* aRetVal) {
diff --git a/widget/CompositorWidget.h b/widget/CompositorWidget.h
index 4515f4ccc0..2f4795364c 100644
--- a/widget/CompositorWidget.h
+++ b/widget/CompositorWidget.h
@@ -63,7 +63,7 @@ class CompositorWidgetDelegate {
 };

 // Platforms that support out-of-process widgets.
-#if defined(XP_WIN) || defined(MOZ_X11)
+#if defined(XP_WIN) || defined(MOZ_X11) || defined(MOZ_WAYLAND)
 // CompositorWidgetParent should implement CompositorWidget and
 // PCompositorWidgetParent.
 class CompositorWidgetParent;
diff --git a/widget/gtk/MozContainer.cpp b/widget/gtk/MozContainer.cpp
index a1c1c2b124..97d31ba5b7 100644
--- a/widget/gtk/MozContainer.cpp
+++ b/widget/gtk/MozContainer.cpp
@@ -9,7 +9,12 @@

 #include <glib.h>
 #include <gtk/gtk.h>
+#ifdef MOZ_X11
 #include <gdk/gdkx.h>
+#endif
+#ifdef MOZ_WAYLAND
+#include "mozilla/WidgetUtilsGtk.h"
+#endif
 #include <stdio.h>

 #ifdef ACCESSIBILITY
diff --git a/widget/gtk/WindowSurfaceProvider.cpp b/widget/gtk/WindowSurfaceProvider.cpp
index 837e8aa696..ae19f3ff70 100644
--- a/widget/gtk/WindowSurfaceProvider.cpp
+++ b/widget/gtk/WindowSurfaceProvider.cpp
@@ -87,7 +87,7 @@ RefPtr<WindowSurface> WindowSurfaceProvider::CreateWindowSurface() {
                                               mXVisual, mXDepth);
     }

-#  ifdef MOZ_HAVE_SHMIMAGE
+#  if defined(MOZ_HAVE_SHMIMAGE) && defined(MOZ_X11)
     if (!mIsShaped && nsShmImage::UseShm()) {
       LOG(("Drawing to Window 0x%lx will use MIT-SHM\n", mXWindow));
       return MakeRefPtr<WindowSurfaceX11SHM>(DefaultXDisplay(), mXWindow,
@@ -95,9 +95,11 @@ RefPtr<WindowSurface> WindowSurfaceProvider::CreateWindowSurface() {
     }
 #  endif  // MOZ_HAVE_SHMIMAGE

+#  if defined(MOZ_X11)
     LOG(("Drawing to Window 0x%lx will use XPutImage\n", mXWindow));
     return MakeRefPtr<WindowSurfaceX11Image>(DefaultXDisplay(), mXWindow,
                                              mXVisual, mXDepth, mIsShaped);
+#  endif
   }
 #endif
   MOZ_RELEASE_ASSERT(false);
diff --git a/widget/gtk/WindowSurfaceWayland.cpp b/widget/gtk/WindowSurfaceWayland.cpp
index 5c74524c21..78e0dc7801 100644
--- a/widget/gtk/WindowSurfaceWayland.cpp
+++ b/widget/gtk/WindowSurfaceWayland.cpp
@@ -15,11 +15,13 @@
 #include "mozilla/gfx/Tools.h"
 #include "gfx2DGlue.h"
 #include "gfxPlatform.h"
+#include "gfxImageSurface.h"
 #include "MozContainer.h"
 #include "mozilla/ScopeExit.h"
 #include "mozilla/StaticPrefs_widget.h"
 #include "mozilla/WidgetUtils.h"
 #include "nsTArray.h"
+#include "prenv.h"

 #ifdef MOZ_LOGGING
 #  include "mozilla/Logging.h"
diff --git a/widget/gtk/components.conf b/widget/gtk/components.conf
index 38c07bd812..a125d8d275 100644
--- a/widget/gtk/components.conf
+++ b/widget/gtk/components.conf
@@ -78,7 +78,7 @@ Classes = [
     },
 ]

-if defined('MOZ_X11'):
+if defined('MOZ_X11') or defined('MOZ_WAYLAND'):
     Classes += [
         {
             'js_name': 'clipboard',
diff --git a/widget/gtk/moz.build b/widget/gtk/moz.build
index b579218ab8..f882569689 100644
--- a/widget/gtk/moz.build
+++ b/widget/gtk/moz.build
@@ -100,23 +100,27 @@ if CONFIG["MOZ_WAYLAND"]:

 if CONFIG["MOZ_X11"]:
     UNIFIED_SOURCES += [
-        "CompositorWidgetChild.cpp",
-        "CompositorWidgetParent.cpp",
-        "InProcessGtkCompositorWidget.cpp",
         "nsClipboardX11.cpp",
         "nsShmImage.cpp",
-        "nsUserIdleServiceGTK.cpp",
         "WindowSurfaceX11.cpp",
         "WindowSurfaceX11Image.cpp",
         "WindowSurfaceX11SHM.cpp",
         "WindowSurfaceXRender.cpp",
     ]
-    EXPORTS.mozilla.widget += [
-        "CompositorWidgetChild.h",
-        "CompositorWidgetParent.h",
-        "GtkCompositorWidget.h",
-        "InProcessGtkCompositorWidget.h",
-    ]
+
+UNIFIED_SOURCES += [
+    "CompositorWidgetChild.cpp",
+    "CompositorWidgetParent.cpp",
+    "InProcessGtkCompositorWidget.cpp",
+    "nsUserIdleServiceGTK.cpp",
+]
+
+EXPORTS.mozilla.widget += [
+    "CompositorWidgetChild.h",
+    "CompositorWidgetParent.h",
+    "GtkCompositorWidget.h",
+    "InProcessGtkCompositorWidget.h",
+]

 if CONFIG["NS_PRINTING"]:
     UNIFIED_SOURCES += [
diff --git a/widget/gtk/mozgtk/mozgtk.c b/widget/gtk/mozgtk/mozgtk.c
index 677f9b3561..b8cb7de58e 100644
--- a/widget/gtk/mozgtk/mozgtk.c
+++ b/widget/gtk/mozgtk/mozgtk.c
@@ -6,6 +6,7 @@

 #include "mozilla/Types.h"

+#if defined(MOZ_X11)
 #include <X11/Xlib.h>
 // Bug 1271100
 // We need to trick system Cairo into not using the XShm extension due to
@@ -19,3 +20,4 @@
 // ever can remove this workaround for system Cairo, we'll need something
 // to replace it for that purpose.
 MOZ_EXPORT Bool XShmQueryExtension(Display* aDisplay) { return False; }
+#endif
diff --git a/widget/gtk/nsClipboard.cpp b/widget/gtk/nsClipboard.cpp
index 74379651b9..a89e8fd8e0 100644
--- a/widget/gtk/nsClipboard.cpp
+++ b/widget/gtk/nsClipboard.cpp
@@ -9,7 +9,9 @@

 #include "nsArrayUtils.h"
 #include "nsClipboard.h"
+#if defined(MOZ_X11)
 #include "nsClipboardX11.h"
+#endif
 #if defined(MOZ_WAYLAND)
 #  include "nsClipboardWayland.h"
 #endif
@@ -32,7 +34,9 @@
 #include "imgIContainer.h"

 #include <gtk/gtk.h>
+#ifdef MOZ_X11
 #include <gtk/gtkx.h>
+#endif

 #include "mozilla/Encoding.h"

@@ -95,10 +99,12 @@ nsClipboard::~nsClipboard() {
 NS_IMPL_ISUPPORTS(nsClipboard, nsIClipboard, nsIObserver)

 nsresult nsClipboard::Init(void) {
+#if defined(MOZ_X11)
   if (widget::GdkIsX11Display()) {
     mContext = MakeUnique<nsRetrievalContextX11>();
-#if defined(MOZ_WAYLAND)
-  } else if (widget::GdkIsWaylandDisplay()) {
+  }
+#elif defined(MOZ_WAYLAND)
+  if (widget::GdkIsWaylandDisplay()) {
     mContext = MakeUnique<nsRetrievalContextWayland>();
 #endif
   } else {
diff --git a/widget/gtk/nsDeviceContextSpecG.cpp b/widget/gtk/nsDeviceContextSpecG.cpp
index b7891d67b5..abe6b82bc0 100644
--- a/widget/gtk/nsDeviceContextSpecG.cpp
+++ b/widget/gtk/nsDeviceContextSpecG.cpp
@@ -6,7 +6,9 @@
 #include "nsDeviceContextSpecG.h"

 #include "mozilla/gfx/PrintTargetPDF.h"
+#ifdef USE_X11
 #include "mozilla/gfx/PrintTargetPS.h"
+#endif
 #include "mozilla/Logging.h"
 #include "mozilla/Services.h"

@@ -46,7 +48,9 @@ using namespace mozilla;
 using mozilla::gfx::IntSize;
 using mozilla::gfx::PrintTarget;
 using mozilla::gfx::PrintTargetPDF;
+#ifdef MOZ_X11
 using mozilla::gfx::PrintTargetPS;
+#endif

 nsDeviceContextSpecGTK::nsDeviceContextSpecGTK()
     : mGtkPrintSettings(nullptr), mGtkPageSetup(nullptr) {}
@@ -119,12 +123,15 @@ already_AddRefed<PrintTarget> nsDeviceContextSpecGTK::MakePrintTarget() {
     return PrintTargetPDF::CreateOrNull(stream, size);
   }

+#ifdef MOZ_X11
   int32_t orientation = mPrintSettings->GetSheetOrientation();
   return PrintTargetPS::CreateOrNull(
       stream, size,
       orientation == nsIPrintSettings::kPortraitOrientation
           ? PrintTargetPS::PORTRAIT
           : PrintTargetPS::LANDSCAPE);
+#endif
+  return nullptr;
 }

 #define DECLARE_KNOWN_MONOCHROME_SETTING(key_, value_) {"cups-" key_, value_},
diff --git a/widget/gtk/nsDragService.cpp b/widget/gtk/nsDragService.cpp
index 6983dc1b2c..2852e232b9 100644
--- a/widget/gtk/nsDragService.cpp
+++ b/widget/gtk/nsDragService.cpp
@@ -23,7 +23,11 @@
 #include "prthread.h"
 #include <dlfcn.h>
 #include <gtk/gtk.h>
+#ifdef MOZ_X11
 #include <gdk/gdkx.h>
+#else
+#include <gdk/gdkwayland.h>
+#endif
 #include "nsCRT.h"
 #include "mozilla/BasicEvents.h"
 #include "mozilla/Services.h"
@@ -33,7 +37,6 @@
 #include "mozilla/WidgetUtilsGtk.h"
 #include "GRefPtr.h"

-#include "gfxXlibSurface.h"
 #include "gfxContext.h"
 #include "nsImageToPixbuf.h"
 #include "nsPresContext.h"
@@ -50,6 +53,8 @@
 #ifdef MOZ_WAYLAND
 #  include "nsClipboardWayland.h"
 #  include "gfxPlatformGtk.h"
+#else
+#  include "gfxXlibSurface.h"
 #endif

 using namespace mozilla;
diff --git a/widget/gtk/nsGtkKeyUtils.cpp b/widget/gtk/nsGtkKeyUtils.cpp
index f4c7030a37..6c5af5394b 100644
--- a/widget/gtk/nsGtkKeyUtils.cpp
+++ b/widget/gtk/nsGtkKeyUtils.cpp
@@ -12,10 +12,12 @@
 #include <gdk/gdkkeysyms.h>
 #include <algorithm>
 #include <gdk/gdk.h>
-#include <gdk/gdkx.h>
 #include <dlfcn.h>
 #include <gdk/gdkkeysyms-compat.h>
+#ifdef MOZ_X11
+#include <gdk/gdkx.h>
 #include <X11/XKBlib.h>
+#endif
 #include "X11UndefineNone.h"
 #include "IMContextWrapper.h"
 #include "WidgetUtils.h"
@@ -51,7 +53,7 @@ LazyLogModule gKeymapWrapperLog("KeymapWrapperWidgets");

 KeymapWrapper* KeymapWrapper::sInstance = nullptr;
 guint KeymapWrapper::sLastRepeatableHardwareKeyCode = 0;
-Time KeymapWrapper::sLastRepeatableKeyTime = 0;
+GTime KeymapWrapper::sLastRepeatableKeyTime = 0;
 KeymapWrapper::RepeatState KeymapWrapper::sRepeatState =
     KeymapWrapper::NOT_PRESSED;

@@ -346,9 +348,11 @@ KeymapWrapper::KeymapWrapper()

   g_object_ref(mGdkKeymap);

+#ifdef MOZ_X11
   if (GdkIsX11Display()) {
     InitXKBExtension();
   }
+#endif

   Init();
 }
@@ -365,16 +369,19 @@ void KeymapWrapper::Init() {
   mModifierKeys.Clear();
   memset(mModifierMasks, 0, sizeof(mModifierMasks));

+#ifdef MOZ_X11
   if (GdkIsX11Display()) {
     InitBySystemSettingsX11();
-  }
+  } else {
+#endif
 #ifdef MOZ_WAYLAND
-  else {
     InitBySystemSettingsWayland();
+#endif
+#ifdef MOZ_X11
   }
+  gdk_window_add_filter(nullptr, FilterEvents, this);
 #endif

-  gdk_window_add_filter(nullptr, FilterEvents, this);

   MOZ_LOG(gKeymapWrapperLog, LogLevel::Info,
           ("%p Init, CapsLock=0x%X, NumLock=0x%X, "
@@ -387,6 +394,7 @@ void KeymapWrapper::Init() {
            GetModifierMask(SUPER), GetModifierMask(HYPER)));
 }

+#ifdef MOZ_X11
 void KeymapWrapper::InitXKBExtension() {
   PodZero(&mKeyboardState);

@@ -619,6 +627,7 @@ void KeymapWrapper::InitBySystemSettingsX11() {
   XFreeModifiermap(xmodmap);
   XFree(xkeymap);
 }
+#endif

 #ifdef MOZ_WAYLAND
 void KeymapWrapper::SetModifierMask(xkb_keymap* aKeymap,
@@ -776,7 +785,9 @@ void KeymapWrapper::InitBySystemSettingsWayland() {
 #endif

 KeymapWrapper::~KeymapWrapper() {
+#ifdef MOZ_X11
   gdk_window_remove_filter(nullptr, FilterEvents, this);
+#endif
   if (mOnKeysChangedSignalHandle) {
     g_signal_handler_disconnect(mGdkKeymap, mOnKeysChangedSignalHandle);
   }
@@ -787,6 +798,7 @@ KeymapWrapper::~KeymapWrapper() {
   MOZ_LOG(gKeymapWrapperLog, LogLevel::Info, ("%p Destructor", this));
 }

+#ifdef MOZ_X11
 /* static */
 GdkFilterReturn KeymapWrapper::FilterEvents(GdkXEvent* aXEvent,
                                             GdkEvent* aGdkEvent,
@@ -900,6 +912,7 @@ GdkFilterReturn KeymapWrapper::FilterEvents(GdkXEvent* aXEvent,

   return GDK_FILTER_CONTINUE;
 }
+#endif

 static void ResetBidiKeyboard() {
   // Reset the bidi keyboard settings for the new GdkKeymap
@@ -1760,6 +1773,7 @@ void KeymapWrapper::InitKeyEvent(WidgetKeyboardEvent& aKeyEvent,
   // state.  It means if there're some pending modifier key press or
   // key release events, the result isn't what we want.
   guint modifierState = aGdkKeyEvent->state;
+#ifdef MOZ_X11
   GdkDisplay* gdkDisplay = gdk_display_get_default();
   if (aGdkKeyEvent->is_modifier && GdkIsX11Display(gdkDisplay)) {
     Display* display = gdk_x11_display_get_xdisplay(gdkDisplay);
@@ -1777,6 +1791,7 @@ void KeymapWrapper::InitKeyEvent(WidgetKeyboardEvent& aKeyEvent,
       }
     }
   }
+#endif
   InitInputEvent(aKeyEvent, modifierState);

   switch (aGdkKeyEvent->keyval) {
@@ -2023,6 +2038,7 @@ bool KeymapWrapper::IsLatinGroup(guint8 aGroup) {
   return result;
 }

+#ifdef MOZ_X11
 bool KeymapWrapper::IsAutoRepeatableKey(guint aHardwareKeyCode) {
   uint8_t indexOfArray = aHardwareKeyCode / 8;
   MOZ_ASSERT(indexOfArray < ArrayLength(mKeyboardState.auto_repeats),
@@ -2030,6 +2046,7 @@ bool KeymapWrapper::IsAutoRepeatableKey(guint aHardwareKeyCode) {
   char bitMask = 1 << (aHardwareKeyCode % 8);
   return (mKeyboardState.auto_repeats[indexOfArray] & bitMask) != 0;
 }
+#endif

 /* static */
 bool KeymapWrapper::IsBasicLatinLetterOrNumeral(uint32_t aCharCode) {
diff --git a/widget/gtk/nsGtkKeyUtils.h b/widget/gtk/nsGtkKeyUtils.h
index 07d60c27a6..43df8095fd 100644
--- a/widget/gtk/nsGtkKeyUtils.h
+++ b/widget/gtk/nsGtkKeyUtils.h
@@ -13,7 +13,9 @@
 #include "nsTArray.h"

 #include <gdk/gdk.h>
+#ifdef MOZ_X11
 #include <X11/XKBlib.h>
+#endif
 #ifdef MOZ_WAYLAND
 #  include <gdk/gdkwayland.h>
 #  include <xkbcommon/xkbcommon.h>
@@ -315,7 +317,9 @@ class KeymapWrapper {
    * See a call of XkbSelectEventDetails() with XkbControlsNotify in
    * InitXKBExtension().
    */
+#ifdef MOZ_X11
   XKeyboardState mKeyboardState;
+#endif

   /**
    * Pointer of the singleton instance.
@@ -326,7 +330,7 @@ class KeymapWrapper {
    * Auto key repeat management.
    */
   static guint sLastRepeatableHardwareKeyCode;
-  static Time sLastRepeatableKeyTime;
+  static GTime sLastRepeatableKeyTime;
   enum RepeatState { NOT_PRESSED, FIRST_PRESS, REPEATING };
   static RepeatState sRepeatState;

diff --git a/widget/gtk/nsPrintDialogGTK.cpp b/widget/gtk/nsPrintDialogGTK.cpp
index 48e9b6521f..461e6b2502 100644
--- a/widget/gtk/nsPrintDialogGTK.cpp
+++ b/widget/gtk/nsPrintDialogGTK.cpp
@@ -26,7 +26,11 @@
 #include "nsIObserverService.h"

 // for gdk_x11_window_get_xid
+#ifdef MOZ_X11
 #include <gdk/gdkx.h>
+#else
+#include <gdk/gdkwayland.h>
+#endif
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -526,6 +530,7 @@ static void wayland_window_handle_exported(GdkWindow* window,
 static gboolean window_export_handle(GtkWindow* window,
                                      GtkWindowHandleExported callback,
                                      gpointer user_data) {
+#ifdef MOZ_X11
   if (GdkIsX11Display()) {
     GdkWindow* gdk_window = gtk_widget_get_window(GTK_WIDGET(window));
     char* handle_str;
@@ -536,8 +541,9 @@ static gboolean window_export_handle(GtkWindow* window,
     g_free(handle_str);
     return true;
   }
+#endif
 #ifdef MOZ_WAYLAND
-  else if (GdkIsWaylandDisplay()) {
+  if (GdkIsWaylandDisplay()) {
     GdkWindow* gdk_window = gtk_widget_get_window(GTK_WIDGET(window));
     WaylandWindowHandleExportedData* data;

diff --git a/widget/gtk/nsUserIdleServiceGTK.cpp b/widget/gtk/nsUserIdleServiceGTK.cpp
index 884d52a6ca..d865b9a236 100644
--- a/widget/gtk/nsUserIdleServiceGTK.cpp
+++ b/widget/gtk/nsUserIdleServiceGTK.cpp
@@ -17,6 +17,7 @@ using mozilla::LogLevel;

 static mozilla::LazyLogModule sIdleLog("nsIUserIdleService");

+#ifdef MOZ_X11
 typedef bool (*_XScreenSaverQueryExtension_fn)(Display* dpy, int* event_base,
                                                int* error_base);

@@ -25,12 +26,15 @@ typedef XScreenSaverInfo* (*_XScreenSaverAllocInfo_fn)(void);
 typedef void (*_XScreenSaverQueryInfo_fn)(Display* dpy, Drawable drw,
                                           XScreenSaverInfo* info);

-static bool sInitialized = false;
 static _XScreenSaverQueryExtension_fn _XSSQueryExtension = nullptr;
 static _XScreenSaverAllocInfo_fn _XSSAllocInfo = nullptr;
 static _XScreenSaverQueryInfo_fn _XSSQueryInfo = nullptr;
+#endif
+
+static bool sInitialized = false;

 static void Initialize() {
+#ifdef MOZ_X11
   if (!mozilla::widget::GdkIsX11Display()) {
     return;
   }
@@ -57,16 +61,22 @@ static void Initialize() {
     MOZ_LOG(sIdleLog, LogLevel::Warning, ("Failed to get XSSAllocInfo!\n"));
   if (!_XSSQueryInfo)
     MOZ_LOG(sIdleLog, LogLevel::Warning, ("Failed to get XSSQueryInfo!\n"));
-
+#endif
   sInitialized = true;
 }

-nsUserIdleServiceGTK::nsUserIdleServiceGTK() : mXssInfo(nullptr) {
+nsUserIdleServiceGTK::nsUserIdleServiceGTK()
+#ifdef MOZ_X11
+: mXssInfo(nullptr)
+#endif
+{
   Initialize();
 }

 nsUserIdleServiceGTK::~nsUserIdleServiceGTK() {
+#ifdef MOZ_X11
   if (mXssInfo) XFree(mXssInfo);
+#endif

 // It is not safe to unload libXScrnSaver until each display is closed because
 // the library registers callbacks through XESetCloseDisplay (Bug 397607).
@@ -88,6 +98,7 @@ bool nsUserIdleServiceGTK::PollIdleTime(uint32_t* aIdleTime) {
   // Ask xscreensaver about idle time:
   *aIdleTime = 0;

+#ifdef MOZ_X11
   // We might not have a display (cf. in xpcshell)
   Display* dplay = GDK_DISPLAY_XDISPLAY(gdk_display_get_default());
   if (!dplay) {
@@ -107,6 +118,7 @@ bool nsUserIdleServiceGTK::PollIdleTime(uint32_t* aIdleTime) {
     *aIdleTime = mXssInfo->idle;
     return true;
   }
+#endif
   // If we get here, we couldn't get to XScreenSaver:
   MOZ_LOG(sIdleLog, LogLevel::Warning, ("XSSQueryExtension returned false!\n"));
   return false;
diff --git a/widget/gtk/nsUserIdleServiceGTK.h b/widget/gtk/nsUserIdleServiceGTK.h
index 9b9ba31846..8f83aee584 100644
--- a/widget/gtk/nsUserIdleServiceGTK.h
+++ b/widget/gtk/nsUserIdleServiceGTK.h
@@ -9,6 +9,7 @@
 #define nsUserIdleServiceGTK_h__

 #include "nsUserIdleService.h"
+#ifdef MOZ_X11
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <gdk/gdkx.h>
@@ -21,6 +22,7 @@ typedef struct {
   unsigned long idle;          // milliseconds idle
   unsigned long event_mask;    // event stuff
 } XScreenSaverInfo;
+#endif

 class nsUserIdleServiceGTK : public nsUserIdleService {
  public:
@@ -40,7 +42,9 @@ class nsUserIdleServiceGTK : public nsUserIdleService {

  private:
   ~nsUserIdleServiceGTK();
+#ifdef MOZ_X11
   XScreenSaverInfo* mXssInfo;
+#endif

  protected:
   nsUserIdleServiceGTK();
diff --git a/widget/gtk/nsWidgetFactory.cpp b/widget/gtk/nsWidgetFactory.cpp
index d649c7e0bf..70b47d5124 100644
--- a/widget/gtk/nsWidgetFactory.cpp
+++ b/widget/gtk/nsWidgetFactory.cpp
@@ -20,9 +20,7 @@
 #include "nsHTMLFormatConverter.h"
 #include "HeadlessClipboard.h"
 #include "IMContextWrapper.h"
-#ifdef MOZ_X11
-#  include "nsClipboard.h"
-#endif
+#include "nsClipboard.h"
 #include "TaskbarProgress.h"
 #include "nsFilePicker.h"
 #include "nsSound.h"
@@ -36,7 +34,6 @@
 using namespace mozilla;
 using namespace mozilla::widget;

-#ifdef MOZ_X11
 NS_IMPL_COMPONENT_FACTORY(nsIClipboard) {
   nsCOMPtr<nsIClipboard> inst;
   if (gfxPlatform::IsHeadless()) {
@@ -51,7 +48,6 @@ NS_IMPL_COMPONENT_FACTORY(nsIClipboard) {

   return inst.forget().downcast<nsISupports>();
 }
-#endif

 nsresult nsWidgetGtk2ModuleCtor() { return nsAppShellInit(); }

diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index f78ce835ef..fdd3580b72 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -57,7 +57,6 @@
 #include "mozilla/UniquePtrExtensions.h"
 #include "mozilla/WidgetUtils.h"
 #include "mozilla/WritingModes.h"
-#include "mozilla/X11Util.h"
 #include "mozilla/XREAppData.h"
 #include "NativeKeyBindings.h"
 #include "nsAppDirectoryServiceDefs.h"
@@ -89,7 +88,6 @@
 #include "ScreenHelperGTK.h"
 #include "SystemTimeConverter.h"
 #include "WidgetUtilsGtk.h"
-#include "mozilla/X11Util.h"

 #ifdef ACCESSIBILITY
 #  include "mozilla/a11y/LocalAccessible.h"
@@ -97,19 +95,23 @@
 #  include "nsAccessibilityService.h"
 #endif

+#include "GLContextEGL.h"  // for GLContextEGL::FindVisual()
+#include "GtkCompositorWidget.h"
 #ifdef MOZ_X11
+#  include "mozilla/X11Util.h"
 #  include <gdk/gdkkeysyms-compat.h>
 #  include <X11/Xatom.h>
 #  include <X11/extensions/XShm.h>
 #  include <X11/extensions/shape.h>
 #  include "gfxXlibSurface.h"
 #  include "GLContextGLX.h"  // for GLContextGLX::FindVisual()
-#  include "GLContextEGL.h"  // for GLContextEGL::FindVisual()
 #  include "WindowSurfaceX11Image.h"
 #  include "WindowSurfaceX11SHM.h"
 #  include "WindowSurfaceXRender.h"
 #endif
 #ifdef MOZ_WAYLAND
+#  include <gdk/gdk.h>
+#  include <gdk/gdkkeysyms-compat.h>
 #  include "nsIClipboard.h"
 #  include "nsView.h"
 #endif
@@ -119,7 +121,9 @@ using namespace mozilla::gfx;
 using namespace mozilla::layers;
 using namespace mozilla::widget;
 using mozilla::gl::GLContextEGL;
+#ifdef MOZ_X11
 using mozilla::gl::GLContextGLX;
+#endif

 // Don't put more than this many rects in the dirty region, just fluff
 // out to the bounding-box if there are more
@@ -278,6 +282,7 @@ bool nsWindow::sTransparentMainWindow = false;

 namespace mozilla {

+#ifdef MOZ_X11
 class CurrentX11TimeGetter {
  public:
   explicit CurrentX11TimeGetter(GdkWindow* aWindow)
@@ -325,6 +330,7 @@ class CurrentX11TimeGetter {
   GdkWindow* mWindow;
   TimeStamp mAsyncUpdateStart;
 };
+#endif

 }  // namespace mozilla

@@ -2342,6 +2348,7 @@ void nsWindow::SetSizeMode(nsSizeMode aMode) {
 }

 static bool GetWindowManagerName(GdkWindow* gdk_window, nsACString& wmName) {
+#ifdef MOZ_X11
   if (!GdkIsX11Display()) {
     return false;
   }
@@ -2408,6 +2415,7 @@ static bool GetWindowManagerName(GdkWindow* gdk_window, nsACString& wmName) {
   }

   wmName = reinterpret_cast<const char*>(prop_return);
+#endif
   return true;
 }

@@ -2465,6 +2473,8 @@ void nsWindow::GetWorkspaceID(nsAString& workspaceID) {
   if (!GdkIsX11Display() || !mShell) {
     return;
   }
+
+#ifdef MOZ_X11
   // Get the gdk window for this widget.
   GdkWindow* gdk_window = gtk_widget_get_window(mShell);
   if (!gdk_window) {
@@ -2493,6 +2503,7 @@ void nsWindow::GetWorkspaceID(nsAString& workspaceID) {

   workspaceID.AppendInt((int32_t)wm_desktop[0]);
   g_free(wm_desktop);
+#endif
 }

 void nsWindow::MoveToWorkspace(const nsAString& workspaceIDStr) {
@@ -2501,7 +2512,7 @@ void nsWindow::MoveToWorkspace(const nsAString& workspaceIDStr) {
   if (NS_FAILED(rv) || !workspaceID || !GdkIsX11Display() || !mShell) {
     return;
   }
-
+#ifdef MOZ_X11
   // Get the gdk window for this widget.
   GdkWindow* gdk_window = gtk_widget_get_window(mShell);
   if (!gdk_window) {
@@ -2535,6 +2546,7 @@ void nsWindow::MoveToWorkspace(const nsAString& workspaceIDStr) {
              SubstructureNotifyMask | SubstructureRedirectMask, &xevent);

   XFlush(xdisplay);
+#endif
 }

 using SetUserTimeFunc = void (*)(GdkWindow*, guint32);
@@ -2575,9 +2587,13 @@ 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();
+#ifdef MOZ_X11
   guint32 timestamp = GdkIsX11Display(gdkDisplay)
                           ? gdk_x11_display_get_user_time(gdkDisplay)
                           : gtk_get_current_event_time();
+#else
+  guint32 timestamp = gtk_get_current_event_time();
+#endif

   if (sLastUserInputTime != GDK_CURRENT_TIME &&
       TimestampIsNewerThan(sLastUserInputTime, timestamp)) {
@@ -2735,6 +2751,7 @@ void nsWindow::UpdateClientOffsetFromFrameExtents() {
     return;
   }

+#ifdef MOZ_X11
   GdkAtom cardinal_atom = gdk_x11_xatom_to_atom(XA_CARDINAL);

   GdkAtom type_returned;
@@ -2768,6 +2785,7 @@ void nsWindow::UpdateClientOffsetFromFrameExtents() {

   LOG(("nsWindow::UpdateClientOffsetFromFrameExtents [%p] %d,%d\n", (void*)this,
        mClientOffset.x, mClientOffset.y));
+#endif
 }

 LayoutDeviceIntPoint nsWindow::GetClientOffset() {
@@ -2778,6 +2796,7 @@ LayoutDeviceIntPoint nsWindow::GetClientOffset() {

 gboolean nsWindow::OnPropertyNotifyEvent(GtkWidget* aWidget,
                                          GdkEventProperty* aEvent) {
+#ifdef MOZ_X11
   if (aEvent->atom == gdk_atom_intern("_NET_FRAME_EXTENTS", FALSE)) {
     UpdateClientOffsetFromFrameExtents();
     return FALSE;
@@ -2786,7 +2805,7 @@ gboolean nsWindow::OnPropertyNotifyEvent(GtkWidget* aWidget,
   if (GetCurrentTimeGetter()->PropertyNotifyHandler(aWidget, aEvent)) {
     return TRUE;
   }
-
+#endif
   return FALSE;
 }

@@ -2924,9 +2943,11 @@ void* nsWindow::GetNativeData(uint32_t aDataType) {
       return GetToplevelWidget();

     case NS_NATIVE_WINDOW_WEBRTC_DEVICE_ID:
+#ifdef MOZ_X11
       if (GdkIsX11Display()) {
         return (void*)GDK_WINDOW_XID(gdk_window_get_toplevel(mGdkWindow));
       }
+#endif
       NS_WARNING(
           "nsWindow::GetNativeData(): NS_NATIVE_WINDOW_WEBRTC_DEVICE_ID is not "
           "handled on Wayland!");
@@ -2946,9 +2967,11 @@ void* nsWindow::GetNativeData(uint32_t aDataType) {
     case NS_NATIVE_OPENGL_CONTEXT:
       return nullptr;
     case NS_NATIVE_EGL_WINDOW: {
+#ifdef MOZ_X11
       if (GdkIsX11Display()) {
         return mGdkWindow ? (void*)GDK_WINDOW_XID(mGdkWindow) : nullptr;
       }
+#endif
 #ifdef MOZ_WAYLAND
       if (mContainer) {
         return moz_container_wayland_get_egl_window(mContainer,
@@ -3289,8 +3312,13 @@ gboolean nsWindow::OnExposeEvent(cairo_t* cr) {
   nsIWidgetListener* listener = GetListener();
   if (!listener) return FALSE;

+#ifdef MOZ_X11
   LOG(("received expose event [%p] %p 0x%lx (rects follow):\n", this,
        mGdkWindow, GdkIsX11Display() ? gdk_x11_window_get_xid(mGdkWindow) : 0));
+#else
+  LOG(("received expose event [%p] %p 0x%lx (rects follow):\n", this,
+       mGdkWindow, 0));
+#endif
   LayoutDeviceIntRegion exposeRegion;
   if (!ExtractExposeRegion(exposeRegion, cr)) {
     return FALSE;
@@ -3819,6 +3847,7 @@ void nsWindow::OnMotionNotifyEvent(GdkEventMotion* aEvent) {
     MOZ_ASSERT(gdk_window, "gdk_window_get_toplevel should not return null");

     bool canDrag = true;
+#ifdef MOZ_X11
     if (GdkIsX11Display()) {
       // Workaround for https://bugzilla.gnome.org/show_bug.cgi?id=789054
       // To avoid crashes disable double-click on WM without _NET_WM_MOVERESIZE.
@@ -3829,6 +3858,7 @@ void nsWindow::OnMotionNotifyEvent(GdkEventMotion* aEvent) {
         canDrag = false;
       }
     }
+#endif

     if (canDrag) {
       gdk_window_begin_move_drag(gdk_window, 1, aEvent->x_root, aEvent->y_root,
@@ -4321,16 +4351,20 @@ TimeStamp nsWindow::GetEventTimeStamp(guint32 aEventTime) {
     int64_t tick =
         BaseTimeDurationPlatformUtils::TicksFromMilliseconds(timestampTime);
     eventTimeStamp = TimeStamp::FromSystemTime(tick);
-  } else {
+  }
+#ifdef MOZ_X11
+  else {
     CurrentX11TimeGetter* getCurrentTime = GetCurrentTimeGetter();
     MOZ_ASSERT(getCurrentTime,
                "Null current time getter despite having a window");
     eventTimeStamp =
         TimeConverter().GetTimeStampFromSystemTime(aEventTime, *getCurrentTime);
   }
+#endif
   return eventTimeStamp;
 }

+#ifdef MOZ_X11
 mozilla::CurrentX11TimeGetter* nsWindow::GetCurrentTimeGetter() {
   MOZ_ASSERT(mGdkWindow, "Expected mGdkWindow to be set");
   if (MOZ_UNLIKELY(!mCurrentTimeGetter)) {
@@ -4338,6 +4372,7 @@ mozilla::CurrentX11TimeGetter* nsWindow::GetCurrentTimeGetter() {
   }
   return mCurrentTimeGetter.get();
 }
+#endif

 gboolean nsWindow::OnKeyPressEvent(GdkEventKey* aEvent) {
   LOG(("OnKeyPressEvent [%p]\n", (void*)this));
@@ -4914,6 +4949,7 @@ static GdkWindow* CreateGdkWindow(GdkWindow* parent, GtkWidget* widget) {
   return window;
 }

+#ifdef MOZ_X11
 // Configure GL visual on X11. We add alpha silently
 // if we use WebRender to workaround NVIDIA specific Bug 1663273.
 bool nsWindow::ConfigureX11GLVisual(bool aUseAlpha) {
@@ -4965,6 +5001,7 @@ bool nsWindow::ConfigureX11GLVisual(bool aUseAlpha) {

   return true;
 }
+#endif

 nsCString nsWindow::GetWindowNodeName() {
   nsCString nodeName("Unknown");
@@ -5552,9 +5589,15 @@ nsresult nsWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
        mWindowType == eWindowType_toplevel ? "Toplevel" : "Popup",
        mIsPIPWindow ? "PIP window" : ""));
   if (mShell) {
+#ifdef MOZ_X11
     LOG(("\tmShell %p mContainer %p mGdkWindow %p 0x%lx\n", mShell, mContainer,
          mGdkWindow,
          GdkIsX11Display() ? gdk_x11_window_get_xid(mGdkWindow) : 0));
+#else
+    LOG(("\tmShell %p mContainer %p mGdkWindow %p 0x%lx\n", mShell, mContainer,
+         mGdkWindow,
+         0));
+#endif
   } else if (mContainer) {
     LOG(("\tmContainer %p mGdkWindow %p\n", mContainer, mGdkWindow));
   } else if (mGdkWindow) {
@@ -6478,6 +6521,7 @@ void nsWindow::UpdateTitlebarTransparencyBitmap() {
     cairo_surface_destroy(surface);
   }

+#ifdef MOZ_X11
   if (!mNeedsShow) {
     Display* xDisplay = GDK_WINDOW_XDISPLAY(mGdkWindow);
     Window xDrawable = GDK_WINDOW_XID(mGdkWindow);
@@ -6500,6 +6544,7 @@ void nsWindow::UpdateTitlebarTransparencyBitmap() {

     XFreePixmap(xDisplay, maskPixmap);
   }
+#endif
 }

 void nsWindow::GrabPointer(guint32 aTime) {
@@ -6772,7 +6817,7 @@ static bool IsFullscreenSupported(GtkWidget* aShell) {
   GdkScreen* screen = gtk_widget_get_screen(aShell);
   GdkAtom atom = gdk_atom_intern("_NET_WM_STATE_FULLSCREEN", FALSE);
   return gdk_x11_screen_supports_net_wm_hint(screen, atom);
-#elif
+#else
   return true;
 #endif
 }
@@ -8048,6 +8093,7 @@ bool nsWindow::GetDragInfo(WidgetMouseEvent* aMouseEvent, GdkWindow** aWindow,
     return false;
   }

+#ifdef MOZ_X11
   if (GdkIsX11Display()) {
     // Workaround for https://bugzilla.gnome.org/show_bug.cgi?id=789054
     // To avoid crashes disable double-click on WM without _NET_WM_MOVERESIZE.
@@ -8063,6 +8109,7 @@ bool nsWindow::GetDragInfo(WidgetMouseEvent* aMouseEvent, GdkWindow** aWindow,
       }
     }
   }
+#endif

   // FIXME: It would be nice to have the widget position at the time
   // of the event, but it's relatively unlikely that the widget has
@@ -8794,6 +8841,7 @@ void nsWindow::GetCompositorWidgetInitData(
     mozilla::widget::CompositorWidgetInitData* aInitData) {
   nsCString displayName;

+#ifdef MOZ_X11
   if (GdkIsX11Display() && mXWindow != X11None) {
     // Make sure the window XID is propagated to X server, we can fail otherwise
     // in GPU process (Bug 1401634).
@@ -8807,6 +8855,12 @@ void nsWindow::GetCompositorWidgetInitData(
   *aInitData = mozilla::widget::GtkCompositorWidgetInitData(
       (mXWindow != X11None) ? mXWindow : (uintptr_t) nullptr, displayName,
       isShaped, GdkIsX11Display(), GetClientSize());
+#else
+  *aInitData = mozilla::widget::GtkCompositorWidgetInitData(
+      (uintptr_t) nullptr,
+      nsCString(), 0,
+      0, GetClientSize());
+#endif
 }

 #ifdef MOZ_WAYLAND
diff --git a/widget/gtk/nsWindow.h b/widget/gtk/nsWindow.h
index 9525c0c6da..6818f7cad2 100644
--- a/widget/gtk/nsWindow.h
+++ b/widget/gtk/nsWindow.h
@@ -90,7 +90,9 @@ typedef struct _GdkEventTouchpadPinch GdkEventTouchpadPinch;

 namespace mozilla {
 class TimeStamp;
+#ifdef MOZ_X11
 class CurrentX11TimeGetter;
+#endif

 }  // namespace mozilla

@@ -271,7 +273,9 @@ class nsWindow final : public nsBaseWidget {

   WidgetEventTime GetWidgetEventTime(guint32 aEventTime);
   mozilla::TimeStamp GetEventTimeStamp(guint32 aEventTime);
+#ifdef MOV_X11
   mozilla::CurrentX11TimeGetter* GetCurrentTimeGetter();
+#endif

   virtual void SetInputContext(const InputContext& aContext,
                                const InputContextAction& aAction) override;
@@ -756,7 +760,9 @@ class nsWindow final : public nsBaseWidget {
    */
   RefPtr<mozilla::widget::IMContextWrapper> mIMContext;

+#ifdef MOZ_X11
   mozilla::UniquePtr<mozilla::CurrentX11TimeGetter> mCurrentTimeGetter;
+#endif
   static GtkWindowDecoration sGtkWindowDecoration;

   static bool sTransparentMainWindow;
@@ -807,6 +813,7 @@ class nsWindow final : public nsBaseWidget {
   void DispatchRestoreEventAccessible();
 #endif

+mozilla::widget::WindowSurfaceProvider mSurfaceProvider;
 #ifdef MOZ_X11
   typedef enum {GTK_WIDGET_COMPOSIDED_DEFAULT = 0,
                 GTK_WIDGET_COMPOSIDED_DISABLED = 1,
@@ -816,7 +823,6 @@ class nsWindow final : public nsBaseWidget {
   Window mXWindow;
   Visual* mXVisual;
   int mXDepth;
-  mozilla::widget::WindowSurfaceProvider mSurfaceProvider;

   bool ConfigureX11GLVisual(bool aUseAlpha);
 #endif
diff --git a/widget/moz.build b/widget/moz.build
index 07e6970e56..9d1fe19661 100644
--- a/widget/moz.build
+++ b/widget/moz.build
@@ -258,7 +258,7 @@ if CONFIG["MOZ_INSTRUMENT_EVENT_LOOP"]:

 EXPORTS.ipc = ["nsGUIEventIPC.h"]

-if CONFIG["MOZ_X11"]:
+if CONFIG["MOZ_X11"] or CONFIG["MOZ_WAYLAND"]:
     DIRS += ["x11"]

 if toolkit in ("cocoa", "windows"):
@@ -305,7 +305,7 @@ if toolkit == "windows":
         "windows/PCompositorWidget.ipdl",
         "windows/PlatformWidgetTypes.ipdlh",
     ]
-elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk" and CONFIG["MOZ_X11"]:
+elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
     IPDL_SOURCES = [
         "gtk/PCompositorWidget.ipdl",
         "gtk/PlatformWidgetTypes.ipdlh",
diff --git a/widget/gtk/moz.build b/widget/gtk/moz.build
index f882569..1acea03 100644
--- a/widget/gtk/moz.build
+++ b/widget/gtk/moz.build
@@ -149,7 +149,7 @@ LOCAL_INCLUDES += [
     "/widget/headless",
 ]

-if CONFIG["MOZ_X11"]:
+if CONFIG["MOZ_X11"] or CONFIG["MOZ_WAYLAND"]:
     LOCAL_INCLUDES += [
         "/widget/x11",
     ]
diff --git a/gfx/thebes/gfxPlatformGtk.cpp b/gfx/thebes/gfxPlatformGtk.cpp
index 12e01681c7..b9f526ff45 100644
--- a/gfx/thebes/gfxPlatformGtk.cpp
+++ b/gfx/thebes/gfxPlatformGtk.cpp
@@ -30,7 +30,9 @@
 #include "mozilla/FontPropertyTypes.h"
 #include "mozilla/gfx/2D.h"
 #include "mozilla/gfx/Logging.h"
+#ifdef MOZ_X11
 #include "mozilla/gfx/XlibDisplay.h"
+#endif
 #include "mozilla/Monitor.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/StaticPrefs_gfx.h"
diff --git a/toolkit/moz.configure b/toolkit/moz.configure
index 2176b41..e3f028a 100644
--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -1172,31 +1172,6 @@ set_define("MOZ_RAW", depends_if("--enable-raw")(lambda _: True))
 # ==============================================================


-@depends(webrtc, when=toolkit_gtk)
-def x11_libs(webrtc):
-    libs = [
-        "x11",
-        "xcb",
-        "xcb-shm",
-        "x11-xcb",
-        "xext",
-        "xrender",
-    ]
-    if webrtc:
-        # third_party/libwebrtc/webrtc/webrtc_gn/moz.build adds those
-        # manually, ensure they're available.
-        libs += [
-            "xcomposite",
-            "xcursor",
-            "xdamage",
-            "xfixes",
-            "xi",
-        ]
-    return " ".join(libs)
-
-
-pkg_check_modules("MOZ_X11", x11_libs, when=toolkit_gtk)
-

 # ASan Reporter Addon
 # ==============================================================
diff --git a/gfx/cairo/cairo/src/cairo-features.h b/gfx/cairo/cairo/src/cairo-features.h
index f7379aa..ceae4f2 100644
--- a/gfx/cairo/cairo/src/cairo-features.h
+++ b/gfx/cairo/cairo/src/cairo-features.h
@@ -55,8 +55,8 @@
 #define CAIRO_HAS_PDF_SURFACE 1
 #endif

-#ifdef MOZ_X11
 #define CAIRO_HAS_PS_SURFACE 1
+#ifdef MOZ_X11
 #define CAIRO_HAS_XLIB_XRENDER_SURFACE 1
 #define CAIRO_HAS_XLIB_SURFACE 1
 #endif