Make dart:dom implementation types private so they don't muddle the docs.

client/dom/scripts/dartgenerator.py

 #!/usr/bin/python
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """This module generates Dart APIs from the IDL database."""
 
 import emitter
 import idlnode
 import logging
@@ skipping 1853 matching lines @@
       # is useful not only for browser compat, but to allow code that links
       # against dart:dom to load in a worker isolate.
       native_spec = '*' + interface_name
 
     if base:
       extends = ' extends ' + base
     elif native_spec[0] == '=':
       # The implementation is a singleton with no prototype.
       extends = ''
     else:
-      extends = ' extends DOMTypeJs'
+      extends = ' extends _DOMTypeJs'
 
     # TODO: Include all implemented interfaces, including other Lists.
     implements = [interface_name]
     element_type = MaybeTypedArrayElementType(self._interface)
     if element_type:
       implements.append('List<' + element_type + '>')
 
     self._members_emitter = self._dart_code.Emit(
         self._template,
         #class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
@@ skipping 13 matching lines @@
     element_type = MaybeTypedArrayElementType(interface)
     if element_type:
       self.AddTypedArrayConstructors(element_type)
 
 
   def FinishInterface(self):
     """."""
     pass
 
   def _ImplClassName(self, type_name):
-    return type_name + 'Js'
+    return '_' + type_name + 'Js'
 
   def _NarrowToImplementationType(self, type_name):
     # TODO(sra): Move into the 'system' and cache the result.
     if type_name == 'EventListener':
       # Callbacks are typedef functions so don't have a class.
       return type_name
     if self._system._database.HasInterface(type_name):
       interface = self._system._database.GetInterface(type_name)
       if _RecognizeCallback(interface):
         # Callbacks are typedef functions so don't have a class.
@@ skipping 112 matching lines @@
       info: An OperationInfo object.
     """
     # TODO(vsm): Handle overloads.
     self._members_emitter.Emit(
         '\n'
         '  $TYPE $NAME($PARAMS) native;\n',
         TYPE=self._NarrowOutputType(info.type_name),
         NAME=info.name,
         PARAMS=info.ParametersImplementationDeclaration(
             lambda type_name: self._NarrowInputType(type_name)))