Remove chromeos==0 blacklist for test_isolation_mode.

build/common.gypi

 # Copyright (c) 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 954 matching lines @@
           'enable_settings_app%': 0,
         }],
 
         # Whether tests targets should be run, archived or just have the
         # dependencies verified. All the tests targets have the '_run' suffix,
         # e.g. base_unittests_run runs the target base_unittests. The test
         # target always calls tools/swarming_client/isolate.py. See the script's
         # --help for more information. Meant to be overriden with GYP_DEFINES.
         # TODO(maruel): Remove the conditions as more configurations are
         # supported.
-        ['OS!="ios" and OS!="android" and chromeos==0', {
+        ['OS!="ios" and OS!="android"', {
           'test_isolation_mode%': 'check',
         }, {
           'test_isolation_mode%': 'noop',
         }],
         # Whether Android build uses OpenMAX DL FFT.
         ['OS=="android" and ((target_arch=="arm" and arm_version >= 7) or target_arch=="ia32" or target_arch=="x64" or target_arch=="arm64" or target_arch=="mipsel")', {
           # Currently only supported on Android ARMv7+, ARM64, ia32, x64 and mipsel.
           # When enabled, this will also enable WebAudio support on
           # Android for these architectures.  Default is enabled.  Whether
           # WebAudio is actually available depends on runtime settings
@@ skipping 5201 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }