Add initial chrome.i18n.getMessage API

lib/renderer/extensions/i18n.js

@@ -0,0 +1,34 @@
+const {ipcRenderer} = require('electron')
+const fs = require('fs')
+const path = require('path')
+
+const getMessagesPath = (language) => {
+  const manifest = ipcRenderer.sendSync('CHROME_I18N_MANIFEST', chrome.runtime.id)
+  let messagesPath = path.join(manifest.srcDirectory, '_locales', language, 'messages.json')
+  if (!fs.statSyncNoException(messagesPath)) {
+    messagesPath = path.join(manifest.srcDirectory, '_locales', manifest.default_locale, 'messages.json')
+  }
+  return messagesPath
+}
+
+const getMessages = (language) => {
+  try {
+    return JSON.parse(fs.readFileSync(getMessagesPath(language))) || {}
+  } catch (error) {
+    return {}
+  }
+}
+
+const getLanguage = () => {
+  return navigator.language.replace(/-.*$/, '').toLowerCase()
+}
+
+module.exports = {
+  getMessage (messageName, substitutions) {
+    const language = getLanguage()
+    const messages = getMessages(language)
+    if (messages.hasOwnProperty(messageName)) {
+      return messages[messageName].message
+    }
+  }
+}