Bug 1498462 - Add Personalization v2, RichText snippets and bug fixes to Activity Stream r=ursula

Differential Revision: https://phabricator.services.mozilla.com/D8588

browser/components/newtab/content-src/asrouter/rich-text-strings.js

@@ -0,0 +1,35 @@
+import {MessageContext} from "fluent";
+
+/**
+ * Properties that allow rich text MUST be added to this list.
+ *   key: the localization_id that should be used
+ *   value: a property or array of properties on the message.content object
+ */
+const RICH_TEXT_CONFIG = {
+  "text": ["text", "scene1_text"],
+  "privacy_html": "scene2_privacy_html",
+};
+
+export const RICH_TEXT_KEYS = Object.keys(RICH_TEXT_CONFIG);
+
+/**
+ * Generates an array of messages suitable for fluent's localization provider
+ * including all needed strings for rich text.
+ * @param {object} content A .content object from an ASR message (i.e. message.content)
+ * @returns {MessageContext[]} A array containing the fluent message context
+ */
+export function generateMessages(content) {
+  const cx = new MessageContext("en-US");
+
+  RICH_TEXT_KEYS.forEach(key => {
+    const attrs = RICH_TEXT_CONFIG[key];
+    const attrsToTry = Array.isArray(attrs) ? [...attrs] : [attrs];
+    let string = "";
+    while (!string && attrsToTry.length) {
+      const attr = attrsToTry.pop();
+      string = content[attr];
+    }
+    cx.addMessages(`${key} = ${string}`);
+  });
+  return [cx];
+}