DevTools: Decouple CSS model from UI entities

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 72 matching lines @@
             'front_end/sdk/ConsoleModel.js',
             'front_end/sdk/ContentProvider.js',
             'front_end/sdk/ContentProviderBasedProjectDelegate.js',
             'front_end/sdk/ContentProviders.js',
             'front_end/sdk/CookieParser.js',
             'front_end/sdk/CPUProfileDataModel.js',
             'front_end/sdk/CPUProfilerModel.js',
             'front_end/sdk/CSSMetadata.js',
             'front_end/sdk/CSSParser.js',
             'front_end/sdk/CSSStyleModel.js',
-            'front_end/sdk/CSSStyleSheetMapping.js',
             'front_end/sdk/CSSWorkspaceBinding.js',
             'front_end/sdk/BreakpointManager.js',
             'front_end/sdk/DOMModel.js',
             'front_end/sdk/DOMStorage.js',
             'front_end/sdk/Database.js',
             'front_end/sdk/DebuggerModel.js',
             'front_end/sdk/DebuggerScriptMapping.js',
             'front_end/sdk/DebuggerWorkspaceBinding.js',
             'front_end/sdk/DefaultScriptMapping.js',
             'front_end/sdk/FileManager.js',
@@ skipping 466 matching lines @@
             'front_end/temp_storage_shared_worker/TempStorageSharedWorker.js',
         ],
         'devtools_script_formatter_worker_js_files': [
             'front_end/script_formatter_worker/CSSFormatter.js',
             'front_end/script_formatter_worker/JavaScriptFormatter.js',
             'front_end/script_formatter_worker/ScriptFormatterWorker.js',
             'front_end/common/utilities.js',
         ],
     },
 }