js_externs_generator: Treat empty object as Object

tools/json_schema_compiler/js_externs_generator.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """
 Generator that produces an externs file for the Closure Compiler.
 Note: This is a work in progress, and generated externs may require tweaking.
 
 See https://developers.google.com/closure/compiler/docs/api-tutorial3#externs
 """
 
@@ skipping 133 matching lines @@
         if prop.type_.property_type is PropertyType.FUNCTION:
           self._AppendFunction(c, prop.type_.function)
         else:
           self._AppendTypeJsDoc(c, prop.type_, prop.optional)
           c.Append()
       self._class_name = None
 
   def _AppendTypedef(self, c, properties):
     """Given an OrderedDict of properties, Appends code containing a @typedef.
     """
-    if not properties: return
+    c.Append('@typedef {')
 
-    c.Append('@typedef {')
-    self._js_util.AppendObjectDefinition(c, self._namespace.name, properties,
-                                         new_line=False)
+    if properties:
+      self._js_util.AppendObjectDefinition(c, self._namespace.name, properties,
+                                           new_line=False)
+    else:
+      c.Append('Object', new_line=False)
+
     c.Append('}', new_line=False)
 
   def _AppendFunction(self, c, function):
     """Appends the code representing a function, including its documentation.
        For example:
 
        /**
         * @param {string} title The new title.
         */
        chrome.window.setTitle = function(title) {};
@@ skipping 50 matching lines @@
        For example, it might return "chrome.namespace".
 
        Also optionally includes the class name if this is in the context
        of outputting the members of a class.
 
        For example, "chrome.namespace.ClassName.prototype"
     """
     if self._class_name:
       return 'chrome.%s.%s.prototype' % (self._namespace.name, self._class_name)
     return 'chrome.%s' % self._namespace.name