Servo's reference embedder (\`examples/winit_minimal.rs\`) handles
resize with a single call: \`webview.resize(new_size)\`. The Servo
paint pipeline behind that call:
1. early-returns if \`rendering_context.size() == new_size\`,
2. otherwise calls \`rendering_context.resize\` itself,
3. updates \`webview_renderer.rect\` so the compositor relays out
the page at the new device viewport,
4. sends \`transaction.set_document_view(...)\` so WebRender's
document viewport matches the surface,
5. flags the painter \`needs_repaint(RepaintReason::Resize)\`.
Our \`runtime.rs::resize\` called \`webview.rendering_context.resize\`
*before* \`webview.webview.resize\`. surfman accepted the new size, so
the painter saw \`rendering_context.size() == new_size\` and took the
early-return path — steps 3, 4, and 5 never ran. The compositor
kept the original (creation-time) viewport rect while we presented
a much larger surface. The page ended up laid out for a tiny
viewport and either rendered into the top-left of a sea of cleared
background (StableLance) or never painted any pipeline at all
(google.com appeared totally blank).
Drop the direct \`rendering_context.resize\` call and route through
\`WebView::resize\` exactly as the reference embedder does. The
debounce in \`record_viewport_size\` still collapses a sidebar /
window-edge animation into a single trailing-edge resize, so we
also avoid hammering Servo with per-frame surface mutations.
ZacharyZhang-NY
d1e811b724