Make per-interface generators an implementation detail of a system.

lib/dom/scripts/systemfrog.py

Index: lib/dom/scripts/systemfrog.py
diff --git a/lib/dom/scripts/systemfrog.py b/lib/dom/scripts/systemfrog.py
index 21faff5e75fae7cbd1c764324c93372c400dd4e6..0deb19a7304423c4c93f523bbf9ee5a9db44f2a6 100644
--- a/lib/dom/scripts/systemfrog.py
+++ b/lib/dom/scripts/systemfrog.py
@@ -29,11 +29,7 @@ class FrogSystem(System):
         templates, database, emitters, output_dir)
     self._impl_file_paths = []
 
-  def InterfaceGenerator(self,
-                         interface,
-                         common_prefix,
-                         super_interface_name,
-                         source_filter):
+  def ProcessInterface(self, interface):
     """."""
     if IsPureInterface(interface.id):
       return
@@ -43,8 +39,7 @@ class FrogSystem(System):
       template = self._templates.Load('frog_impl.darttemplate')
 
     dart_code = self._ImplFileEmitter(interface.id)
-    return FrogInterfaceGenerator(self, interface, template,
-                                  super_interface_name, dart_code)
+    FrogInterfaceGenerator(self, interface, template, dart_code).Generate()
 
   def GenerateLibraries(self):
     self._GenerateLibFile(
@@ -68,7 +63,7 @@ class FrogSystem(System):
 class FrogInterfaceGenerator(BaseGenerator):
   """Generates a Frog class for a DOM IDL interface."""
 
-  def __init__(self, system, interface, template, super_interface, dart_code):
+  def __init__(self, system, interface, template, dart_code):
     """Generates Dart code for the given interface.
 
     Args:
@@ -77,16 +72,13 @@ class FrogInterfaceGenerator(BaseGenerator):
           been converted to Dart types (e.g. int, String), unless they are in
           the same package as the interface.
       template: A string template.
-      super_interface: A string or None, the name of the common interface that
-          this interface implements, if any.
       dart_code: an Emitter for the file containing the Dart implementation
           class.
     """
-    super(FrogInterfaceGenerator, self).__init__(system._database)
+    super(FrogInterfaceGenerator, self).__init__(system._database, interface)
     self._system = system
     self._interface = interface
     self._template = template
-    self._super_interface = super_interface
     self._dart_code = dart_code
     self._current_secondary_parent = None