libservo: Move size handling to RenderContext from WindowMethods (#35621)

This is the first step toward removing `WindowMethods`, which will
gradually be integrated into the `WebView` and `WebViewDelegate`. Sizing
of the `WebView` is now handled by the a size associated with a
`RenderingContext`. `WebView`s will eventually just paint the entire
size of their `RenderingContext`. Notes:

- This is transitionary step so now there is a `WebView::resize` and a
  `WebView::move_resize`. The first is the future which will resize the
  `WebView` and its associated `RenderingContext`. The second is a
  function that the virtual `WebView`s that will soon be replaced by a
  the one-`WebView` per `WebView` model.
- We do not need to call `WebView::move_resize` at as much any longer
  because the default size of the `WebView` is to take up the whole
  `RenderingContext`.
- `SurfmanRenderingContext` is no longer exposed in the API, as a
  surfman context doesn't naturally have a size unless a surface is
  bound to it.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

ports/servoshell/desktop/headless_window.rs

@@ -86,7 +86,7 @@ impl WindowPortsMethods for Window {
         // Because we are managing the rendering surface ourselves, there will be no other
         // notification (such as from the display manager) that it has changed size, so we
         // must notify the compositor here.
-        webview.notify_rendering_context_resized();
+        webview.resize(PhysicalSize::new(size.width as u32, size.height as u32));
 
         Some(new_size)
     }
@@ -149,10 +149,7 @@ impl WindowPortsMethods for Window {
 
 impl WindowMethods for Window {
     fn get_coordinates(&self) -> EmbedderCoordinates {
-        let inner_size = self.inner_size.get();
         EmbedderCoordinates {
-            viewport: Box2D::from_origin_and_size(Point2D::zero(), inner_size),
-            framebuffer: inner_size,
             window_rect: self.window_rect,
             screen_size: self.screen_size,
             available_screen_size: self.screen_size,