Changed look of pin keyboard.

chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * 'pin-keyboard' is a keyboard that can be used to enter PINs or more generally
  * numeric values.
  *
  * Properties:
@@ skipping 44 matching lines @@
    * Fires an update event with the current PIN value. The event will only be
    * fired if the PIN value has actually changed.
    * @param {string} value
    * @param {string} previous
    */
   onPinValueChange_: function(value, previous) {
     if (value != previous)
       this.fire('pin-change', { pin: value });
   },
 
+  /** Called when the user wants to erase the last character of the entered
+   *  PIN value.
+   */
+  onPinClear_: function() {
+    this.value = this.value.substring(0, this.value.length - 1);
+  },
+
   /** Called when a key event is pressed while the input element has focus. */
   onInputKeyDown_: function(event) {
     // Up/down pressed, swallow the event to prevent the input value from
     // being incremented or decremented.
     if (event.keyCode == 38 || event.keyCode == 40) {
       event.preventDefault();
       return;
     }
 
     // Enter pressed.
     if (event.keyCode == 13) {
       this.firePinSubmitEvent_();
       event.preventDefault();
       return;
     }
   }
 });