cros: HTML fixes needed to reinitializing an existing lock WebUI.

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

Index: chrome/browser/resources/chromeos/login/lock.js
diff --git a/chrome/browser/resources/chromeos/login/lock.js b/chrome/browser/resources/chromeos/login/lock.js
index ad5919ce956cc5801e881bee324b882ccd243731..3325755e99d559d2d5edad85a2caf71f03deb0f5 100644
--- a/chrome/browser/resources/chromeos/login/lock.js
+++ b/chrome/browser/resources/chromeos/login/lock.js
@@ -66,6 +66,39 @@ cr.define('cr.ui.Oobe', function() {
       chrome.send('screenStateInitialize');
     },
 
+    /**
+     * Notification from the host that the PIN keyboard will be used in the
+     * lock session so it should also get preloaded.
+     */
+    preloadPin: function() {

[Alexander Alekseev, 2016/12/10 01:26:49]

nit: rename to preloadPinKeyboard 

[jdufault, 2016/12/12 19:52:02]

Done.

+      showPinKeyboardAsync();
+    },
+
+    /**
+     * Called when a preloaded webview (this) instance is being reused to
+     * display a new lock screen session. This will also be called when a
+     * lock screen has been preloaded and is being displayed for the first
+     * time.
+     */
+    reload: function() {
+      // Sending accountPickerReady displays the webui. Wait for the next
+      // animation frame so the user does not see any state from the previous
+      // instance.
+      requestAnimationFrame(function() {
+        chrome.send('accountPickerReady');
+      });
+    },
+
+    /**
+     * Called when the lock screen has been dismissed but this webview will stay
+     * in memory. The webview will be reused when Oobe.reload() is called.
+     */
+    teardown: function() {
+      // The PIN keyboard will disable the virtual keyboard. Make sure to
+      // revert the force disable when hiding the lock screen.
+      chrome.send('setForceDisableVirtualKeyboard', [false]);
+    },
+
     // Dummy Oobe functions not present with stripped login UI.
     initializeA11yMenu: function(e) {},
     handleAccessibilityLinkClick: function(e) {},