flatc now become deterministic.

tools/determinism/deterministic_build_whitelist.pyl

 # Copyright 2016 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.
 #
 # This is a .pyl, or "Python Literal", file. You can treat it just like a
 # .json file, with the following exceptions:
 # * all keys must be quoted (use single quotes, please);
 # * comments are allowed, using '#' syntax; and
 # * trailing commas are allowed.
 #
 # List of files that are known to be non deterministic. This is a "temporary"
 # workaround to find regression on the deterministic builders.
 #
 # PNaCl general bug: https://crbug.com/429358
 #
 # TODO(sebmarchand): Remove this once all the files are deterministic.
 {
   # https://crbug.com/383340
   'android': [
-    'flatc',
   ],
 
   # https://crbug.com/330263
   'linux': [
-    'flatc',
     # https://crbug.com/654989
     'ppapi_nacl_tests_pnacl_newlib_x32_nonsfi.nexe',
     'ppapi_nacl_tests_pnacl_newlib_x64.nexe',
   ],
 
   # https://crbug.com/330262
   'mac': [
     'accelerated_widget_mac_unittests',
     'accessibility_unittests',
     'angle_end2end_tests',
@@ skipping 39 matching lines @@
     'device_unittests',
     'display_compositor_benchmark',
     'display_compositor_gl_tests',
     'display_unittests',
     'events_unittests',
     'extensions_browsertests',
     'extensions_unittests',
     'ffmpeg_regression_tests',
     'filesystem_service_unittests',
     'filter_fuzz_stub',
-    'flatc',
     'gcm_unit_tests',
     'generate_barcode_video',
     'generate_timecode_audio',
     'gfx_unittests',
     'gin_unittests',
     'gles2_conform_support',
     'gles2_conform_test',
     'gl_tests',
     'gl_unittests',
     'gn_unittests',
@@ skipping 273 matching lines @@
     'views_mus_interactive_ui_tests.exe',
     'views_mus_unittests.exe',
     'views_unittests.exe',
     'webkit_unit_tests.exe',
     'webtest_library.dll',
     'window_type_launcher_library.dll',
     'wm_unittests.exe',
     'wtf_unittests.exe',
   ],
 }