Add @abstract to allowed Closure linter tags

third_party/closure_compiler/closure_args.gypi

 # Copyright 2015 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.
 
+# GN version: third_party/closure_compiler/closure_args.gni
 {
   'closure_args': [
     'compilation_level=SIMPLE_OPTIMIZATIONS',
+
+    # Keep this in sync with chrome/browser/web_dev_style/js_checker.py.
     'extra_annotation_name=attribute',
     'extra_annotation_name=demo',
     'extra_annotation_name=element',
     'extra_annotation_name=group',
     'extra_annotation_name=hero',
     'extra_annotation_name=homepage',
     'extra_annotation_name=status',
     'extra_annotation_name=submodule',
+
     'jscomp_error=accessControls',
     'jscomp_error=ambiguousFunctionDecl',
     'jscomp_error=checkTypes',
     'jscomp_error=checkVars',
     'jscomp_error=constantProperty',
     'jscomp_error=deprecated',
     'jscomp_error=externsValidation',
     'jscomp_error=globalThis',
     'jscomp_error=invalidCasts',
     'jscomp_error=missingProperties',
     'jscomp_error=missingReturn',
     'jscomp_error=nonStandardJsDocs',
     'jscomp_error=suspiciousCode',
     'jscomp_error=undefinedNames',
     'jscomp_error=undefinedVars',
     'jscomp_error=unknownDefines',
     'jscomp_error=uselessCode',
     'jscomp_error=visibility',
+
     'language_in=ECMASCRIPT6_STRICT',
     'language_out=ECMASCRIPT5_STRICT',
+
     'polymer_pass',
+
     'source_map_format=V3',
   ],
   'default_disabled_closure_args': [
     # TODO(dbeam): happens when the same file is <include>d multiple times.
     'jscomp_off=duplicate',
     # TODO(fukino): happens when cr.defineProperty() has a type annotation.
     # Avoiding parse-time warnings needs 2 pass compiling. crbug.com/421562.
     'jscomp_off=misplacedTypeAnnotation',
   ]
 }