[DevTools] Cleanup frontend-in-iframe support.

Source/devtools/devtools.gypi

 #
 # Copyright (C) 2013 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 31 matching lines @@
             '<@(devtools_emulation_js_files)',
             '<@(devtools_host_js_files)',
             '<@(devtools_main_js_files)',
             '<@(devtools_platform_js_files)',
             '<@(devtools_sdk_js_files)',
             '<@(devtools_toolbox_bootstrap_js_files)',
             '<@(devtools_ui_js_files)',
             '<@(devtools_workspace_js_files)',
             '<@(devtools_core_css_files)',
         ],
+        'devtools_compatibility_scripts': [
+            'front_end/devtools.js',
+        ],
         'devtools_core_base_files': [
             'front_end/inspector.css',
             'front_end/inspector.js',
             'front_end/inspector.json',
             'front_end/toolbox.css',
             'front_end/toolbox.js',
             'front_end/toolbox.json',
             'front_end/Runtime.js',
         ],
         'devtools_core_css_files': [
@@ skipping 682 matching lines @@
             'front_end/Images/toolbarItemSelected.png',
             'front_end/Images/touchCursor.png',
             'front_end/Images/touchCursor_2x.png',
             'front_end/Images/updateServiceWorker.svg',
         ],
         'devtools_extension_api_files': [
             'front_end/extensions/ExtensionAPI.js',
         ],
     },
 }