Remove Webkit prefix from all members and make experimental.

tools/dom/scripts/systemhtml.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 provides shared functionality for the system to generate
 Dart:html APIs from the IDL database."""
 
 import emitter
 import os
 from generator import *
 from htmldartgenerator import *
 
 _js_custom_members = set([
     'ArrayBuffer.slice',
     'AudioBufferSourceNode.start',
     'AudioBufferSourceNode.stop',
     'AudioContext.createGain',
     'AudioContext.createScriptProcessor',
+    'CanvasRenderingContext2D.lineDashOffset',
     'Console.memory',
     'Console.profiles',
     'Console.assertCondition',
     'Console.count',
     'Console.debug',
     'Console.dir',
     'Console.dirxml',
     'Console.error',
     'Console.group',
     'Console.groupCollapsed',
@@ skipping 895 matching lines @@
 
       self._members_emitter.Emit(
           '  $RENAME$ANNOTATIONS$MODIFIERS$TYPE$TARGET($PARAMS) native;\n',
           RENAME=self._RenamingAnnotation(info.declared_name, target),
           ANNOTATIONS=self._Annotations(info.type_name, info.declared_name),
           MODIFIERS='static ' if info.IsStatic() else '',
           TYPE=TypeOrNothing(native_return_type),
           TARGET=target,
           PARAMS=', '.join(target_parameters))
 
-    declaration = '%s%s %s(%s)' % (
+    declaration = '%s%s%s %s(%s)' % (
+        self._Annotations(info.type_name, info.declared_name),
         'static ' if info.IsStatic() else '',
         return_type,
         html_name,
         info.ParametersDeclaration(InputType))
     self._GenerateDispatcherBody(
         operations,
         parameter_names,
         declaration,
         GenerateCall,
         self._IsOptional,
@@ skipping 161 matching lines @@
     for library_name in libraries:
       self._libraries[library_name] = DartLibrary(
           library_name, template_loader, library_type, output_dir)
 
   def AddFile(self, basename, library_name, path):
     self._libraries[library_name].AddFile(path)
 
   def Emit(self, emitter, auxiliary_dir):
     for lib in self._libraries.values():
       lib.Emit(emitter, auxiliary_dir)