Repro race condition with signInWithRedirect in demo app

Author: prameshj

packages/auth/demo/package.json

@@ -18,7 +18,7 @@
   },
   "dependencies": {
     "@firebase/app": "0.7.24",
-    "@firebase/auth": "0.20.1",
+    "@firebase/auth": "file:..",
     "@firebase/logger": "0.3.2",
     "@firebase/util": "1.6.0",
     "tslib": "^2.1.0"

packages/auth/demo/src/index.js

@@ -1812,6 +1812,19 @@ function initApp() {
   },
   onAuthError);
 
+  // Try once upon page load, not on subsequent loads.
+  if (sessionStorage.getItem("prameshj-test") !== "done") {
+  console.log("Starting redirect sign in upon page load.");
+  try {
+    sessionStorage.setItem("prameshj-test", "done");
+    signInWithRedirect(auth, new GoogleAuthProvider(), browserPopupRedirectResolver).catch(onAuthError);
+  } catch (error) {
+    console.log('Error while calling signInWithRedirect');
+    console.error(error);
+  }
+
+  }
+
   // Bootstrap tooltips.
   $('[data-toggle="tooltip"]').tooltip();