Bug 1645677 [Wayland] Update EGLSurface when wl_surface is deleted r=emilio,jgilbert

When GtkWidget is hidden, underlying wl_surface is deleted. We need to also update EGLSurface of GtkWidget (GtkCompositorWidget)
as EGLSurface is directly linked to wl_surface:

- When GtkWidget is hidden, call GtkCompositorWidget::DisableRendering(). That releases GtkCompositorWidget resources
  related to GtkWidget (XWindow/XVisual etc.) and marks the widget as hidden.
- If GtkWidget is backed by EGL call compositor resume which forces compositor to create new EGLSurface.
- Make sure GLContextEGL can create EGLSurface even when GtkWidget is hidden and wl_surface is missing.
  It prevents fallback to SW rendering or pause RenderCompositorEGL which leads to Bug 1777664 (whole browser UI freeze).
- Return early from RenderCompositorEGL::BeginFrame()/RenderCompositorEGL::EndFrame() when GtkCompositorWidget is hidden.

Depends on D157357

Differential Revision: https://phabricator.services.mozilla.com/D157358

gfx/gl/GLContextProviderEGL.cpp

@@ -346,6 +346,18 @@ EGLSurface GLContextEGL::CreateEGLSurfaceForCompositorWidget(
   }
 
   MOZ_ASSERT(aCompositorWidget);
+#ifdef MOZ_WAYLAND
+  // RenderCompositorEGL does not like EGL_NO_SURFACE as it fallbacks
+  // to SW rendering or claims itself as paused.
+  // In case we're missing valid native window because aCompositorWidget hidden,
+  // just create a fallback EGLSurface.
+  // Actual EGLSurface will be created by widget code later when
+  // aCompositorWidget becomes visible.
+  if (widget::GdkIsWaylandDisplay() && aCompositorWidget->IsHidden()) {
+    mozilla::gfx::IntSize pbSize(16, 16);
+    return CreateWaylandBufferSurface(*egl, aConfig, pbSize);
+  }
+#endif
   EGLNativeWindowType window =
       GET_NATIVE_WINDOW_FROM_COMPOSITOR_WIDGET(aCompositorWidget);
   if (!window) {

gfx/webrender_bindings/RenderCompositorEGL.cpp

@@ -127,6 +127,11 @@ RenderedFrameId RenderCompositorEGL::EndFrame(
 #endif
 
   RenderedFrameId frameId = GetNextRenderFrameId();
+#ifdef MOZ_WAYLAND
+  if (mWidget->IsHidden()) {
+    return frameId;
+  }
+#endif
   if (mEGLSurface != EGL_NO_SURFACE && aDirtyRects.Length() > 0) {
     gfx::IntRegion bufferInvalid;
     const auto bufferSize = GetBufferSize();

widget/gtk/nsWindow.cpp

@@ -3442,6 +3442,10 @@ void* nsWindow::GetNativeData(uint32_t aDataType) {
 #endif
 #ifdef MOZ_WAYLAND
       if (GdkIsWaylandDisplay()) {
+        if (mCompositorWidgetDelegate) {
+          MOZ_DIAGNOSTIC_ASSERT(
+              !mCompositorWidgetDelegate->AsGtkCompositorWidget()->IsHidden());
+        }
         eglWindow = moz_container_wayland_get_egl_window(
             mContainer, FractionalScaleFactor());
       }
@@ -4059,6 +4063,26 @@ void nsWindow::OnMap() {
 
 void nsWindow::OnUnmap() {
   LOG("nsWindow::OnUnmap");
+
+  // wl_surface owned by mContainer is going to be deleted.
+  // Make sure we don't paint to it on Wayland.
+  if (GdkIsWaylandDisplay() && mCompositorWidgetDelegate) {
+    mCompositorWidgetDelegate->DisableRendering();
+  }
+#ifdef MOZ_WAYLAND
+  if (moz_container_wayland_has_egl_window(mContainer)) {
+    // Widget is backed by OpenGL EGLSurface created over wl_surface
+    // owned by mContainer.
+    // RenderCompositorEGL::Resume() deletes recent EGLSurface based on
+    // wl_surface owned by mContainer and creates a new fallback EGLSurface.
+    // Then we can delete wl_surface in moz_container_wayland_unmap().
+    // We don't want to pause compositor as it may lead to whole
+    // browser freeze (Bug 1777664).
+    if (CompositorBridgeChild* remoteRenderer = GetRemoteRenderer()) {
+      remoteRenderer->SendResume();
+    }
+  }
+#endif
   moz_container_wayland_unmap(GTK_WIDGET(mContainer));
 }