js_externs_generator: Treat empty object as Object

tools/json_schema_compiler/js_externs_generator.py

Index: tools/json_schema_compiler/js_externs_generator.py
diff --git a/tools/json_schema_compiler/js_externs_generator.py b/tools/json_schema_compiler/js_externs_generator.py
index a5ef075ac260f574782cf4d06f974e3e662c0e79..f8d697125b766a74ca47efaff90fb674e5ea92d7 100644
--- a/tools/json_schema_compiler/js_externs_generator.py
+++ b/tools/json_schema_compiler/js_externs_generator.py
@@ -151,11 +151,14 @@ class _Generator(object):
   def _AppendTypedef(self, c, properties):
     """Given an OrderedDict of properties, Appends code containing a @typedef.
     """
-    if not properties: return
-
     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):