fix: crash in WebFrameMain mojo connection when RenderFrameHost is nu…

…llptr (#34411)

* fix: crash when RenderFrameHost is nullptr

* chore: lint fix

Co-authored-by: samuelmaddock <samuel.maddock@gmail.com>

shell/browser/api/electron_api_web_frame_main.cc

@@ -193,8 +193,13 @@ void WebFrameMain::MaybeSetupMojoConnection() {
     renderer_api_.set_disconnect_handler(base::BindOnce(
         &WebFrameMain::OnRendererConnectionError, weak_factory_.GetWeakPtr()));
   }
+
+  // Render frame should exist when this method is called.
+  DCHECK(render_frame_);
+
   // Wait for RenderFrame to be created in renderer before accessing remote.
-  if (pending_receiver_ && render_frame_->IsRenderFrameCreated()) {
+  if (pending_receiver_ && render_frame_ &&
+      render_frame_->IsRenderFrameCreated()) {
     render_frame_->GetRemoteInterfaces()->GetInterface(
         std::move(pending_receiver_));
   }