Convert ExtensionFrameHost to RenderFrameHostReceiverSet.

https://chromium-review.googlesource.com/c/chromium/src/+/3063358

shell/browser/electron_browser_client.cc

@@ -1458,6 +1458,15 @@ bool ElectronBrowserClient::BindAssociatedReceiverFromFrame(
     return true;
   }
 #endif
+#if BUILDFLAG(ENABLE_EXTENSIONS)
+  if (interface_name == extensions::mojom::LocalFrameHost::Name_) {
+    extensions::ExtensionWebContentsObserver::BindLocalFrameHost(
+        mojo::PendingAssociatedReceiver<extensions::mojom::LocalFrameHost>(
+            std::move(*handle)),
+        render_frame_host);
+    return true;
+  }
+#endif
 
   return false;
 }