--- a/dom/bindings/Configuration.py
+++ b/dom/bindings/Configuration.py
@@ -4,22 +4,40 @@
 
 from WebIDL import IDLImplementsStatement
 import os
 from collections import defaultdict
 
 autogenerated_comment = "/* THIS FILE IS AUTOGENERATED - DO NOT EDIT */\n"
 
 
-class Configuration:
+class DescriptorProvider:
+    """
+    A way of getting descriptors for interface names
+    """
+    def __init__(self, config, workers):
+        self.config = config
+        self.workers = workers
+
+    def getDescriptor(self, interfaceName):
+        """
+        Gets the appropriate descriptor for the given interface name given the
+        context of the current descriptor. This selects the appropriate
+        implementation for cases like workers.
+        """
+        return self.config.getDescriptor(interfaceName, self.workers)
+
+
+class Configuration(DescriptorProvider):
     """
     Represents global configuration state based on IDL parse data and
     the configuration file.
     """
     def __init__(self, filename, parseData, generatedEvents=[]):
+        DescriptorProvider.__init__(self, self, False)
 
         # Read the configuration file.
         glbl = {}
         execfile(filename, glbl)
         config = glbl['DOMInterfaces']
 
         # Build descriptors for all the interfaces we have in the parse data.
         # This allows callers to specify a subset of interfaces by filtering
@@ -299,33 +317,16 @@ class Configuration:
         return DescriptorProvider(self, workers)
 
 
 class NoSuchDescriptorError(TypeError):
     def __init__(self, str):
         TypeError.__init__(self, str)
 
 
-class DescriptorProvider:
-    """
-    A way of getting descriptors for interface names
-    """
-    def __init__(self, config, workers):
-        self.config = config
-        self.workers = workers
-
-    def getDescriptor(self, interfaceName):
-        """
-        Gets the appropriate descriptor for the given interface name given the
-        context of the current descriptor. This selects the appropriate
-        implementation for cases like workers.
-        """
-        return self.config.getDescriptor(interfaceName, self.workers)
-
-
 def methodReturnsJSObject(method):
     assert method.isMethod()
     if method.returnsPromise():
         return True
 
     for signature in method.signatures():
         returnType = signature[0]
         if returnType.isObject() or returnType.isSpiderMonkeyInterface():