build(aio): move the transforms folder into the tools folder

aio/tools/transforms/angular.io-package/processors/processNavigationMap.js

@@ -0,0 +1,51 @@
+module.exports = function processNavigationMap(versionInfo, log) {
+  return {
+    $runAfter: ['paths-computed'],
+    $runBefore: ['rendering-docs'],
+    $process: function(docs) {
+
+      const navigationDoc = docs.find(doc => doc.docType === 'navigation-json');
+
+      if (!navigationDoc) {
+        throw new Error(
+          'Missing navigation map document (docType="navigation-json").' +
+          'Did you forget to add it to the readFileProcessor?');
+      }
+
+      // Verify that all the navigation paths are to valid docs
+      const pathMap = {};
+      docs.forEach(doc => pathMap[doc.path] = true);
+      const errors = walk(navigationDoc.data, pathMap, []);
+
+      if (errors.length) {
+        log.error(`Navigation doc: ${navigationDoc.fileInfo.relativePath} contains invalid urls`);
+        // eslint-disable-next-line no-console
+        console.log(errors);
+        // TODO(petebd): fail if there are errors: throw new Error('processNavigationMap failed');
+      }
+
+      // Add in the version data in a "secret" field to be extracted in the docs app
+      navigationDoc.data['__versionInfo'] = versionInfo.currentVersion;
+    }
+  };
+};
+
+function walk(node, map, path) {
+  let errors = [];
+  for(const key in node) {
+    const child = node[key];
+    if (key === 'url') {
+      const url = child.replace(/#.*$/, ''); // strip hash
+      if (isRelative(url) && !map[url]) {
+        errors.push({ path: path.join('.'), url });
+      }
+    } else if (typeof child !== 'string') {
+      errors = errors.concat(walk(child, map, path.concat([key])));
+    }
+  }
+  return errors;
+}
+
+function isRelative(url) {
+  return !/^(https?:)?\/\//.test(url);
+}