Pin keyboard works with virtual keyboard.

ui/login/display_manager.js

Index: ui/login/display_manager.js
diff --git a/ui/login/display_manager.js b/ui/login/display_manager.js
index 626bf7b9181b6e4643c9350491013aedfdb12a58..96e7f6cb546bdf419a3a75f3b833a081348fc882 100644
--- a/ui/login/display_manager.js
+++ b/ui/login/display_manager.js
@@ -204,6 +204,12 @@ cr.define('cr.ui.login', function() {
     forceKeyboardFlow_: false,
 
     /**
+     * Whether the virtual keyboard is displayed.
+     * @type {boolean}
+     */
+    virtualKeyboardShown: false,
+
+    /**
      * Type of UI.
      * @type {string}
      */
@@ -256,6 +262,11 @@ cr.define('cr.ui.login', function() {
       $('login-header-bar').hidden = hidden;
     },
 
+    set pinHidden(hidden) {
+      this.virtualKeyboardShown = hidden;
+      $('pod-row').setPinHidden(hidden);
+    },
+
     /**
      * Sets the current size of the client area (display size).
      * @param {number} width client area width