Bug 1664804 - Allow external surfaces for WebGL again. r=jgilbert

This check was previously added in bug 1628175, and then accidentally removed in bug 1632249.

Differential Revision: https://phabricator.services.mozilla.com/D91671

gfx/layers/ShareableCanvasRenderer.cpp

@@ -126,6 +126,9 @@ void ShareableCanvasRenderer::UpdateCompositableClient() {
   if (!YIsDown()) {
     flags |= TextureFlags::ORIGIN_BOTTOM_LEFT;
   }
+  if (IsOpaque()) {
+    flags |= TextureFlags::IS_OPAQUE;
+  }
 
   // -
 

gfx/layers/opengl/MacIOSurfaceTextureHostOGL.cpp

@@ -229,11 +229,13 @@ void MacIOSurfaceTextureHostOGL::PushDisplayItems(
     case gfx::SurfaceFormat::B8G8R8X8: {
       MOZ_ASSERT(aImageKeys.length() == 1);
       MOZ_ASSERT(mSurface->GetPlaneCount() == 0);
+      // We disable external compositing for RGB surfaces for now until
+      // we've tested support more thoroughly. Bug 1667917.
       aBuilder.PushImage(aBounds, aClip, true, aFilter, aImageKeys[0],
                          !(mFlags & TextureFlags::NON_PREMULTIPLIED),
                          wr::ColorF{1.0f, 1.0f, 1.0f, 1.0f},
                          preferCompositorSurface,
-                         /* aSupportsExternalCompositing */ true);
+                         /* aSupportsExternalCompositing */ false);
       break;
     }
     case gfx::SurfaceFormat::YUV422: {