Add public API generation with cr.makePublic() and handle it in compiler pass

ui/webui/resources/js/cr.js

Index: ui/webui/resources/js/cr.js
diff --git a/ui/webui/resources/js/cr.js b/ui/webui/resources/js/cr.js
index 94c7553714cdc167a2c7bf87009f7416b80aae33..87d56111a09bad17866b19ccd769847ea1438bbd 100644
--- a/ui/webui/resources/js/cr.js
+++ b/ui/webui/resources/js/cr.js
@@ -294,6 +294,30 @@ var cr = function() {
     };
   }
 
+  /**
+   * Forwards public APIs to private implementations.
+   * @param {Function} ctor Constructor that have private implementations in its
+   *     prototype.
+   * @param {Array.<string>} publicAPI List of public method names that have
+   *     their underscored counterparts in constructor's prototype.
+   * @param {HTMLElement=} opt_target Target node (used in
+   *     oobe_screen_user_image.js)
+   */
+  function makePublic(ctor, publicAPI, opt_target) {
+    publicAPI.forEach(function(name) {
+      if (opt_target) {
+        ctor[name] = function(value) {
+          opt_target[name + '_'](value);
+        };
+      } else {
+        ctor[name] = function() {
+          var instance = ctor.getInstance();
+          return instance[name + '_'].apply(instance, arguments);
+        };
+      }
+    });
+  }
+
   return {
     addSingletonGetter: addSingletonGetter,
     createUid: createUid,
@@ -303,6 +327,7 @@ var cr = function() {
     dispatchSimpleEvent: dispatchSimpleEvent,
     exportPath: exportPath,
     getUid: getUid,
+    makePublic: makePublic,
     PropertyKind: PropertyKind,
 
     get doc() {