Added strings of i18n and made the pin-keyboard work for rtl lang.

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">
   <template>
     <style>
       #root {
+        direction: ltr;
         display: flex;
       }
 
       .row {
         display: flex;
       }
 
       .row.horizontal-center {
         justify-content: center;
       }
@@ skipping 72 matching lines @@
       /* Ensure that all children of paper-button do not consume events. This
        * 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"
+          <input id="pin-input" type="number"
                  value="{{value::input}}"
                  on-keydown="onInputKeyDown_"></input>
           <div class="digit-button first-row">
             <paper-button class="digit-button submit-button"
                           on-tap="firePinSubmitEvent_">
               <div class="icon-container">
                   <iron-icon class="icon" icon="icons:forward"><iron-icon>
               </div>
             </paper-button>
           </div>
         </div>
 
         <div class="row keyboard">
           <paper-button class="digit-button" on-tap="onNumberTap_" value="1">
-            <inner-text>1</inner-text>
+            <inner-text>$i18n{pinKeyboard1}</inner-text>
           </paper-button>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="2">
-            <inner-text>2</inner-text>
+            <inner-text>$i18n{pinKeyboard2}</inner-text>
           </paper-button>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="3">
-            <inner-text>3</inner-text>
+            <inner-text>$i18n{pinKeyboard3}</inner-text>
           </paper-button>
         </div>
         <div class="row keyboard">
           <paper-button class="digit-button" on-tap="onNumberTap_" value="4">
-            <inner-text>4</inner-text>
+            <inner-text>$i18n{pinKeyboard4}</inner-text>
           </paper-button>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="5">
-            <inner-text>5</inner-text>
+            <inner-text>$i18n{pinKeyboard5}</inner-text>
           </paper-button>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="6">
-            <inner-text>6</inner-text>
+            <inner-text>$i18n{pinKeyboard6}</inner-text>
           </paper-button>
         </div>
         <div class="row keyboard">
           <paper-button class="digit-button" on-tap="onNumberTap_" value="7">
-            <inner-text>7</inner-text>
+            <inner-text>$i18n{pinKeyboard7}</inner-text>
           </paper-button>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="8">
-            <inner-text>8</inner-text>
+            <inner-text>$i18n{pinKeyboard8}</inner-text>
           </paper-button>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="9">
-            <inner-text>9</inner-text>
+            <inner-text>$i18n{pinKeyboard9}</inner-text>
           </paper-button>
         </div>
         <div class="row keyboard">
           <div class="digit-button"></div>
           <paper-button class="digit-button" on-tap="onNumberTap_" value="0">
-            <inner-text>0</inner-text>
+            <inner-text>$i18n{pinKeyboard0}</inner-text>
           </paper-button>
           <paper-button class="digit-button clear-button" on-tap="onPinClear_">
             <div class="icon-container">
               <iron-icon class="icon" icon="icons:clear"><iron-icon>
             </div>
-            <inner-text class="icon-subheading">Clear</inner-text>
+            <inner-text class="icon-subheading">
+              $i18n{pinKeyboardClear}
+            </inner-text>
           </paper-button>
         </div>
       </div>
     </div>
   </template>
   <script src="pin_keyboard.js"></script>
 </dom-module>