libservo: Expose SoftwareRenderingContext and WindowRenderingContext (#35501)

Expose two easy-to-use wrappers around `SurfmanRenderingContext` that
make the API simpler to use:

- `WindowRenderingContext`: This `RenderingContext` is a newtype around
  `SurfmanRenderingContext` takes a `raw-window-handle` display and window
  and creates a full window rendering context.
- `SoftwareRenderingContext`: is wraps `SurfmanRenderingContext` and
  adds a swap chain in order to expose a software GL rendering context.

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

components/shared/webrender/lib.rs

@@ -28,8 +28,6 @@ use webrender_api::{
     ImageKey, NativeFontHandle, PipelineId as WebRenderPipelineId,
 };
 
-pub use crate::rendering_context::SurfmanRenderingContext;
-
 #[derive(Deserialize, Serialize)]
 pub enum CrossProcessCompositorMessage {
     /// Inform WebRender of the existence of this pipeline.