cros: Fix Gaia flashing on 2nd show

chrome/browser/resources/chromeos/login/screen_gaia_signin.js

Index: chrome/browser/resources/chromeos/login/screen_gaia_signin.js
diff --git a/chrome/browser/resources/chromeos/login/screen_gaia_signin.js b/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
index 05abdf5fd1e912e8064a1794d9ccd77143431a34..6a06b34b72cf07977bde96d9c27cc53d2d32c007 100644
--- a/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
+++ b/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
@@ -333,8 +333,12 @@ login.createScreen('GaiaSigninScreen', 'gaia-signin', function() {
      */
     showLoadingUI_: function(show) {
       $('gaia-loading').hidden = !show;
-      this.getSigninFrame_().hidden = show;
       this.classList.toggle('loading', show);
+      // Only set hidden for offline-gaia and not set it on the 'sign-frame'
+      // webview element. Setting it on webview not only hides but also affects
+      // its loading events.
+      if (this.isOffline)
+        this.getSigninFrame_().hidden = show;
       $('signin-frame').classList.remove('show');
       this.updateControlsState();
     },