Support alt text for Extension error icons

The extension error icons (which convey the severity of the issue) have no alt text.
so a person using a screen reader won't be able to differentiate the error severity.

BUG=476174

Review URL: https://codereview.chromium.org/1552353003

Cr-Commit-Position: refs/heads/master@{#369114}

3 files changed, 20 insertions, 3 deletions

diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 9d66217..73275c9 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -4451,6 +4451,15 @@ Even if you have downloaded files from this website before, the website might ha
         <message name="IDS_EXTENSIONS_SHOW_BUTTON" desc="The text for the Show link.">
           Show button
         </message>
+        <message name="IDS_EXTENSIONS_LOG_LEVEL_INFO" desc="Alt-text indicating a low severity level for the error icon in the chrome://extensions page.">
+          Log
+        </message>
+        <message name="IDS_EXTENSIONS_LOG_LEVEL_WARN" desc="Alt-text indicating a medium severity level for the error icon in the chrome://extensions page.">
+          Warning
+        </message>
+        <message name="IDS_EXTENSIONS_LOG_LEVEL_ERROR" desc="Alt-text indicating a high severity level for the error icon in the chrome://extensions page.">
+          Error
+        </message>
         <message name="IDS_MD_EXTENSIONS_ITEM_ID" desc="The text for the label next to the extension id.">
           &lt;span&gt;ID:&lt;/span&gt;<ph name="EXTENSION_ID">$1<ex>cfhdojbkjhnklbpkdaibdccddilifddb</ex></ph>
         </message>
diff --git a/chrome/browser/resources/extensions/extension_error.js b/chrome/browser/resources/extensions/extension_error.js
index 0f50425..7853a15 100644
--- a/chrome/browser/resources/extensions/extension_error.js
+++ b/chrome/browser/resources/extensions/extension_error.js
@@ -67,18 +67,21 @@ cr.define('extensions', function() {
        * @type {(ManifestError|RuntimeError)}
        */
       this.error = error;
+      var iconAltTextKey = 'extensionLogLevelWarn';
 
       // Add an additional class for the severity level.
       if (error.type == chrome.developerPrivate.ErrorType.RUNTIME) {
         switch (error.severity) {
           case chrome.developerPrivate.ErrorLevel.LOG:
             this.classList.add('extension-error-severity-info');
+            iconAltTextKey = 'extensionLogLevelInfo';
             break;
           case chrome.developerPrivate.ErrorLevel.WARN:
             this.classList.add('extension-error-severity-warning');
             break;
           case chrome.developerPrivate.ErrorLevel.ERROR:
             this.classList.add('extension-error-severity-fatal');
+            iconAltTextKey = 'extensionLogLevelError';
             break;
           default:
             assertNotReached();
@@ -90,9 +93,7 @@ cr.define('extensions', function() {
 
       var iconNode = document.createElement('img');
       iconNode.className = 'extension-error-icon';
-      // TODO(hcarmona): Populate alt text with a proper description since this
-      // icon conveys the severity of the error. (info, warning, fatal).
-      iconNode.alt = '';
+      iconNode.alt = loadTimeData.getString(iconAltTextKey);
       this.insertBefore(iconNode, this.firstChild);
 
       var messageSpan = this.querySelector('.extension-error-message');
diff --git a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
index 5fdbfd2..3203c31 100644
--- a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
+++ b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
@@ -193,6 +193,13 @@ void ExtensionSettingsHandler::GetLocalizedValues(
                     l10n_util::GetStringUTF16(
                         IDS_EXTENSIONS_DISABLED_UPDATE_REQUIRED_BY_POLICY));
 
+  source->AddLocalizedString("extensionLogLevelInfo",
+                             IDS_EXTENSIONS_LOG_LEVEL_INFO);
+  source->AddLocalizedString("extensionLogLevelWarn",
+                             IDS_EXTENSIONS_LOG_LEVEL_WARN);
+  source->AddLocalizedString("extensionLogLevelError",
+                             IDS_EXTENSIONS_LOG_LEVEL_ERROR);
+
   // TODO(estade): comb through the above strings to find ones no longer used in
   // uber extensions.
   source->AddString("extensionUninstall",