Revert 111450 - disabling Mutation Observers on Chromium branch 1025

Source/WebKit/chromium/features.gypi

 #
 # Copyright (C) 2009 Google Inc. All rights reserved.
 # 
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 # 
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 101 matching lines @@
     # We have to nest variables inside variables so that they can be overridden
     # through GYP_DEFINES.
     'variables': {
       'use_accelerated_compositing%': 1,
       'enable_skia_text%': 0,
       'enable_svg%': 1,
       'enable_viewport%': 0,
       'enable_touch_events%': 1,
       'use_skia%': 0,
       'enable_touch_icon_loading%' : 0,
-      'enable_mutation_observers%': 0,
+      'enable_mutation_observers%': 1,
     },
     'use_accelerated_compositing%': '<(use_accelerated_compositing)',
     'enable_skia_text%': '<(enable_skia_text)',
     'enable_svg%': '<(enable_svg)',
     'enable_touch_events%': '<(enable_touch_events)',
     'use_skia%': '<(use_skia)',
     'conditions': [
       ['OS=="android"', {
         'feature_defines': [
           'ENABLE_WEB_AUDIO=0',
@@ skipping 33 matching lines @@
       }],
       ['OS=="mac"', {
         'feature_defines': [
           'ENABLE_RUBBER_BANDING=1',
           'WTF_USE_SKIA_ON_MAC_CHROMIUM=<(use_skia)',
         ],
       }],
     ],
   },
 }