Add ChromeVox support for Assistant optin flow

Bug: 930994
Test: Manual Test
Change-Id: I18da4e8c5767002c709f72293c76c8e67259d1d9
Reviewed-on: https://chromium-review.googlesource.com/c/1484231Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Yue Li <updowndota@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635209}

chrome/browser/resources/chromeos/assistant_optin/assistant_get_more.html

@@ -8,10 +8,12 @@
     <link rel="stylesheet" href="assistant_get_more.css">
     <link rel="stylesheet" href="assistant_shared_styles.css">
     <oobe-dialog id="get-more-dialog" role="dialog" has-buttons hide-shadow
-        no-footer-padding no-header>
+        no-footer-padding no-header
+        i18n-values="aria-label:assistantReadyTitle">
       <div slot="footer">
         <div class="container">
-          <img id="logo" src="assistant_logo.png">
+          <img id="logo" src="assistant_logo.png"
+              i18n-values="aria-label:assistantLogo">
           <div class="title" i18n-content="assistantReadyTitle"></div>
           <div class="content" id="intro-text"
               i18n-content="assistantReadyMessage"></div>

chrome/browser/resources/chromeos/assistant_optin/assistant_loading.html

@@ -14,7 +14,8 @@
         no-footer-padding no-header>
       <div slot="footer">
         <div class="container" id="error-container">
-          <img id="logo" src="assistant_logo.png">
+          <img id="logo" src="assistant_logo.png"
+              i18n-values="aria-label:assistantLogo">
           <div class="title" i18n-content="assistantOptinLoadErrorTitle"></div>
           <div class="sub-title" i18n-content="assistantOptinLoadErrorMessage">
           </div>

chrome/browser/resources/chromeos/assistant_optin/assistant_third_party.html

@@ -12,7 +12,8 @@
         no-footer-padding no-header>
       <div slot="footer">
         <div class="container">
-          <img id="logo" src="assistant_logo.png">
+          <img id="logo" src="assistant_logo.png"
+              i18n-values="aria-label:assistantLogo">
           <div class="title" id="title-text"></div>
           <div class="line"></div>
           <div id="insertion-point"></div>

chrome/browser/resources/chromeos/assistant_optin/assistant_third_party.js

@@ -111,6 +111,8 @@ Polymer({
    * Reload the page with the given consent string text data.
    */
   reloadContent: function(data) {
+    this.$['third-party-dialog'].setAttribute(
+        'aria-label', data['thirdPartyTitle']);
     this.$['title-text'].textContent = data['thirdPartyTitle'];
     this.$['next-button-text'].textContent = data['thirdPartyContinueButton'];
     this.$['footer-text'].innerHTML =

chrome/browser/resources/chromeos/assistant_optin/assistant_value_prop.html

@@ -14,7 +14,8 @@
         role="dialog" has-buttons no-footer-padding no-header>
       <div slot="footer">
         <div class="container">
-          <img id="logo" src="assistant_logo.png">
+          <img id="logo" src="assistant_logo.png"
+              i18n-values="aria-label:assistantLogo">
           <div class="title" id="title-text"></div>
           <div class="content" id="intro-text"></div>
           <div class="flex layout horizontal center">

chrome/browser/resources/chromeos/assistant_optin/assistant_value_prop.js

@@ -241,6 +241,8 @@ Polymer({
    * Reload the page with the given consent string text data.
    */
   reloadContent: function(data) {
+    this.$['value-prop-dialog'].setAttribute(
+        'aria-label', data['valuePropTitle']);
     this.$['user-image'].src = data['valuePropUserImage'];
     this.$['title-text'].textContent = data['valuePropTitle'];
     this.$['intro-text'].textContent = data['valuePropIntro'];

chrome/browser/resources/chromeos/assistant_optin/assistant_voice_match.html

@@ -10,10 +10,12 @@
     <link rel="stylesheet" href="assistant_shared_styles.css">
     <link rel="stylesheet" href="assistant_voice_match.css">
     <oobe-dialog id="voice-match-dialog" role="dialog" has-buttons hide-shadow
-        no-footer-padding no-header class="intro">
+        no-footer-padding no-header class="intro"
+        i18n-values="aria-label:assistantVoiceMatchTitle">
       <div slot="footer">
         <div class="container">
-          <img id="logo" src="assistant_logo.png">
+          <img id="logo" src="assistant_logo.png"
+              i18n-values="aria-label:assistantLogo">
           <div id="intro-container">
             <div class="title" i18n-content="assistantVoiceMatchTitle"></div>
             <div class="content"

chrome/browser/ui/webui/chromeos/login/assistant_optin_flow_screen_handler.cc

@@ -59,6 +59,7 @@ AssistantOptInFlowScreenHandler::~AssistantOptInFlowScreenHandler() {
 void AssistantOptInFlowScreenHandler::DeclareLocalizedValues(
     ::login::LocalizedValuesBuilder* builder) {
   builder->Add("locale", g_browser_process->GetApplicationLocale());
+  builder->Add("assistantLogo", IDS_VOICE_INTERACTION_LOGO);
   builder->Add("assistantOptinLoading",
                IDS_VOICE_INTERACTION_VALUE_PROP_LOADING);
   builder->Add("assistantOptinLoadErrorTitle",