Add optional schema compiler error messages

chrome/chrome_tests_unit.gypi

 # Copyright 2012 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.
 {
   'targets': [
     {
       # This target contains mocks and test utilities that don't belong in
       # production libraries but are used by more than one test executable.
       'target_name': 'test_support_common',
       'type': 'static_library',
@@ skipping 1901 matching lines @@
         '../tools/json_schema_compiler/test/arrays_unittest.cc',
         '../tools/json_schema_compiler/test/callbacks_unittest.cc',
         '../tools/json_schema_compiler/test/choices_unittest.cc',
         '../tools/json_schema_compiler/test/crossref_unittest.cc',
         '../tools/json_schema_compiler/test/enums_unittest.cc',
         '../tools/json_schema_compiler/test/functions_as_parameters_unittest.cc',
         '../tools/json_schema_compiler/test/functions_on_types_unittest.cc',
         '../tools/json_schema_compiler/test/idl_schemas_unittest.cc',
         '../tools/json_schema_compiler/test/objects_unittest.cc',
         '../tools/json_schema_compiler/test/simple_api_unittest.cc',
+        '../tools/json_schema_compiler/test/error_generation_unittest.cc',
         '../ui/views/test/desktop_test_views_delegate.cc',
         '../ui/views/test/desktop_test_views_delegate.h',
         '../ui/views/test/test_views_delegate.cc',
         '../ui/views/test/test_views_delegate.h',
         '../ui/views/test/views_test_base.cc',
         '../ui/views/test/views_test_base.h',
         '../ui/webui/resources/js/cr.js',
         '../webkit/browser/blob/mock_blob_url_request_context.cc',
         '../webkit/browser/blob/mock_blob_url_request_context.h',
         '../webkit/browser/quota/mock_storage_client.cc',
@@ skipping 761 matching lines @@
               # more details.
               'DebugInformationFormat': '3',
               'ProgramDataBaseFileName': '<(PRODUCT_DIR)/unit_tests.exe.pdb',
             },
           },
         },
       ],
     }],
   ],  # 'conditions'
 }