Convert snakecase enum names to camelcase when stringified.

ui/accessibility/ax_enums.idl

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // These should be kept in sync with third_party/WebKit/public/web/WebAXEnums.h
 // until the Chromium and Blink trees are merged.
-namespace ui {
+[camel_case_enum_to_string=true] namespace ui {
   enum AXEvent {
     activedescendantchanged,
     alert,
     aria_attribute_changed,
     autocorrection_occured,
     blur,
     checked_state_changed,
     children_changed,
     focus,
     hide,
@@ skipping 324 matching lines @@
     ax_attr_word_ends
   };
 
   [cpp_omit_enum_type] enum AXTextDirection {
     ax_text_direction_lr,
     ax_text_direction_rl,
     ax_text_direction_tb,
     ax_text_direction_bt
   };
 };