ChromeOS: Implement Language Selection screen of material design OOBE.

chrome/browser/resources/chromeos/login/oobe_welcome.html

 <!-- 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. -->
 
 <link rel="import" href="chrome://resources/cr_elements/network/cr_network_icon.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_network_select.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_onc_types.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/classes/iron-flex-layout.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-iconset-svg/iron-iconset-svg.html">
 
 <iron-iconset-svg name="oobe-welcome" size="24">
   <svg>
     <defs>
       <g id="add"><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"></path></g>
       <g id="wifi"><path d="M1 9l2 2c4.97-4.97 13.03-4.97 18 0l2-2C16.93 2.93 7.08 2.93 1 9zm8 8l3 3 3-3c-1.65-1.66-4.34-1.66-6 0zm-4-4l2 2c2.76-2.76 7.24-2.76 10 0l2-2C15.14 9.14 8.87 9.14 5 13z"></path></g>
     </defs>
   </svg>
 </iron-iconset-svg>
 
 <dom-module name="oobe-welcome-md">
   <link rel="stylesheet" href="oobe_welcome.css">
   <template>
-    <oobe-card id="welcomeSection" class="fit" hidden="[[networkSelectionScreenShown]]">
+    <oobe-card id="welcomeSection" class="fit" hidden="[[!welcomeScreenShown]]">
       <div class="header flex vertical layout end-justified start">
         <h1 class="welcome-message" i18n-content="networkScreenGreeting"></h1>
       </div>
       <div class="footer flex vertical layout justified">
         <div class="welcome-next flex vertical layout center">
-          <oobe-next-button id="welcomeNextButton" on-tap="onWelcomeNextButtonClicked_"></oobe-next-button>
+          <oobe-next-button id="welcomeNextButton"
+              on-tap="onWelcomeNextButtonClicked_">
+          </oobe-next-button>
         </div>
         <div class="flex horizontal layout justified">
-          <div class="buttonbox layout vertical">
-            <iron-icon icon="icons:language" class="bottom-button self-center"></iron-icon>
+          <div class="buttonbox layout vertical"
+              on-tap="onWelcomeSelectLanguageButtonClicked_">
+            <iron-icon icon="icons:language" class="bottom-button self-center">
+            </iron-icon>
             <div id="currentLanguage">[[currentLanguage]]</div>
           </div>
           <div class="buttonbox layout vertical">
-            <iron-icon icon="icons:accessibility" class="bottom-button self-center"></iron-icon>
+            <iron-icon icon="icons:accessibility"
+                class="bottom-button self-center">
+            </iron-icon>
             <div id="accessibilityLabel" i18n-content="accessibilityLink"></div>
           </div>
         </div>
       </div>
     </oobe-card>
-    <oobe-dialog id="networkSection" class="fit" hidden="[[!networkSelectionScreenShown]]">
+    <oobe-dialog class="fit" hidden="[[!languageSelectionScreenShown]]"
+        has-buttons>
+      <iron-icon icon="icons:language" class="oobe-icon"></iron-icon>
+      <div class="header flex layout vertical end-justified start">
+        <h1 class="welcome-message" i18n-content="languageSectionTitle"></h1>
+      </div>
+      <div class="footer layout vertical">
+        <template is="dom-if" if="[[enabled]]">
+          <div id="languageDropdownContainer"
+              class="flex layout horizontal justified language-selection-entry">
+            <div class="layout vertical center-justified"
+                i18n-content="languageDropdownTitle">
+            </div>
+            <oobe-i18n-dropdown id="languageSelect" items="[[languages]]"
+                on-select-item="onLanguageSelected_"
+                label="$i18n{languageDropdownTitle}">
+            </oobe-i18n-dropdown>
+          </div>
+          <div id="keyboardDropdownContainer"
+              class="flex layout horizontal justified language-selection-entry">
+            <div class="layout vertical center-justified"
+                i18n-content="keyboardDropdownTitle">
+            </div>
+            <oobe-i18n-dropdown id="keyboardSelect" items="[[keyboards]]"
+                on-select-item="onKeyboardSelected_"
+                label="$i18n{keyboardDropdownTitle}">
+            </oobe-i18n-dropdown>
+          </div>
+        </template>
+      </div>
+      <div class="bottom-buttons layout horizontal">
+        <oobe-text-button inverse on-tap="closeLanguageSection_"
+          i18n-content="oobeOKButtonText">
+        </oobe-text-button>
+      </div>
+    </oobe-dialog>
+    <oobe-dialog id="networkSection" class="fit"
+        hidden="[[!networkSelectionScreenShown]]">
       <iron-icon icon="oobe-welcome:wifi" class="oobe-icon"></iron-icon>
-      <div class="header flex vertical layout end-justified start">
+      <div class="header flex layout vertical end-justified start">
         <h1 class="welcome-message" i18n-content="networkSectionTitle"></h1>
         <h1 class="welcome-message-hint" i18n-content="networkSectionHint"></h1>
       </div>
-      <div class="footer flex vertical layout justified">
+      <div class="footer flex layout vertical justified">
         <cr-network-select id="networkSelect"
             on-network-connected="onNetworkConnected_"
             on-network-item-selected="onNetworkListNetworkItemSelected_"
             on-custom-item-selected="onNetworkListCustomItemSelected_"
             custom-items="[[_getNetworkCustomItems()]]"
             max-height="280">
         </cr-network-select>
       </div>
     </oobe-dialog>
   </template>
 </dom-module>