Pin keyboard works with virtual keyboard.

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

Index: chrome/browser/resources/chromeos/login/login_shared.js
diff --git a/chrome/browser/resources/chromeos/login/login_shared.js b/chrome/browser/resources/chromeos/login/login_shared.js
index 0c50cd4ef9ba91c4d6eca8b37033f32217ffa71f..77439f3643b0a9c8a5b07f74d4d168dcee081cd8 100644
--- a/chrome/browser/resources/chromeos/login/login_shared.js
+++ b/chrome/browser/resources/chromeos/login/login_shared.js
@@ -394,6 +394,13 @@ cr.define('cr.ui', function() {
   };
 
   /**
+   * Shows/hides pin keyboard on the lock screen.
+   */
+  Oobe.showPinKeyboard = function(show) {
+    Oobe.getInstance().pinHidden = !show;
+  };
+
+  /**
    * Sets the current size of the client area (display size).
    * @param {number} width client area width
    * @param {number} height client area height