Expose some internal PIN keyboard state.

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

 <!-- TODO(crbug.com/603217): Use i18n instead of string literals. Figure out
                              what i18n to use for keypad, ie, does 1 ABC make
                              sense in every scenario? -->
 
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/paper-styles.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/iron-icons.html">
 
 <dom-module id="pin-keyboard">

[xiyuan, 2016/06/21 20:16:24]

Can we add some document for this polymer element? What properties does it
expose and what events does it fire etc.

[jdufault, 2016/06/22 22:58:53]

Done.

   <template>
     <style>
       #root {
         display: flex;
       }
 
       /* TODO(jdufault): Remove this CSS once we inline the PIN element with the
        * user-pod. */
       #container-constrained-width {
         -webkit-tap-highlight-color: transparent;
@@ skipping 70 matching lines @@
        * simplifies the event handler code. */
       paper-button * {
         pointer-events: none;
       }
     </style>
 
     <div id="root">
       <div id="container-constrained-width">
         <div class="row horizontal-center">
           <input id="pin-input" type="number" placeholder="Enter PIN"
+                 value="{{value::input}}"
                  on-keydown="onInputKeyDown_"></input>
         </div>
 
         <div class="row keyboard">
           <paper-button class="digit-button" on-tap="onNumberTap_" value="1">
             <inner-text>1</inner-text>
           </paper-button>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="2">
             <inner-text>2<subhead>ABC</subhead></inner-text>
           </paper-button>
@@ skipping 23 matching lines @@
             <inner-text>9<subhead>WXYZ</subhead></inner-text>
           </paper-button>
         </div>
         <div class="row keyboard">
           <div class="digit-button"></div>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="0">
             <inner-text>0</inner-text>
           </paper-button>
           <div class="digit-button">
             <paper-icon-button class="digit-button submit-button"
-                               icon="icons:check" on-tap="onPinSubmit_">
+                               icon="icons:check" on-tap="firePinSubmitEvent_">
             </paper-icon-button>
           </div>
         </div>
       </div>
     </div>
   </template>
   <script src="pin_keyboard.js"></script>
 </dom-module>