Bug 1684194 [Linux] Use RenderCompositorEGL on X11/EGL, r=sotaro

Differential Revision: https://phabricator.services.mozilla.com/D108508

gfx/gl/GLContextProviderEGL.cpp

@@ -255,7 +255,7 @@ already_AddRefed<GLContext> GLContextEGLFactory::CreateImpl(
   int visualID = 0;
 #ifdef MOZ_X11
   GdkDisplay* gdkDisplay = gdk_display_get_default();
-  if (GdkIsX11Display(gdkDisplay)) {
+  if (GdkIsX11Display(gdkDisplay) && aWindow) {
     auto* display = GDK_DISPLAY_XDISPLAY(gdkDisplay);
     if (display) {
       XWindowAttributes windowAttrs;

gfx/webrender_bindings/RenderCompositorEGL.cpp

@@ -36,7 +36,7 @@ namespace mozilla::wr {
 UniquePtr<RenderCompositor> RenderCompositorEGL::Create(
     RefPtr<widget::CompositorWidget> aWidget, nsACString& aError) {
 #ifdef MOZ_WAYLAND
-  if (!mozilla::widget::GdkIsWaylandDisplay()) {
+  if (!gfx::gfxVars::UseEGL()) {
     return nullptr;
   }
 #endif

gfx/webrender_bindings/RenderThread.cpp

@@ -1125,7 +1125,7 @@ static already_AddRefed<gl::GLContext> CreateGLContext(nsACString& aError) {
 #elif defined(MOZ_WIDGET_ANDROID)
   gl = CreateGLContextEGL();
 #elif defined(MOZ_WAYLAND)
-  if (mozilla::widget::GdkIsWaylandDisplay()) {
+  if (gfx::gfxVars::UseEGL()) {
     gl = CreateGLContextEGL();
   }
 #elif XP_MACOSX

widget/gtk/nsWindow.cpp

@@ -4861,6 +4861,14 @@ nsresult nsWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
       // the drawing window
       mGdkWindow = gtk_widget_get_window(eventWidget);
 
+#ifdef MOZ_WAYLAND
+      if (mIsX11Display && gfx::gfxVars::UseEGL() && isAccelerated) {
+        mCompositorInitiallyPaused = true;
+        mNeedsCompositorResume = true;
+        MaybeResumeCompositor();
+      }
+#endif
+
       if (mWindowType == eWindowType_popup) {
         // gdk does not automatically set the cursor for "temporary"
         // windows, which are what gtk uses for popups.