Collect UMA statistics on which chrome://flags lead to chrome restart on ChromeOS.

chrome/unit_tests.isolate

 # 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.
 {
   'conditions': [
     ['OS=="android" or OS=="linux"', {
       'variables': {
         'isolate_dependency_untracked': [
           '<(PRODUCT_DIR)/test_data/',
         ],
       },
     }],
     ['OS=="android" or OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'isolate_dependency_tracked': [
           '../third_party/accessibility-audit/axs_testing.js',
+          '../tools/metrics/histograms/histograms.xml',
           '<(PRODUCT_DIR)/resources.pak',
         ],
         'isolate_dependency_untracked': [
           '../base/test/data/',
           '../components/test/data/',
           '../extensions/test/data/',
           '../net/data/',
           '../third_party/hunspell_dictionaries/',
           '../third_party/zlib/google/test/data/',
           'test/data/',
@@ skipping 98 matching lines @@
         'isolate_dependency_untracked': [
           '../chromeos/test/data/network/',
         ],
       },
     }],
   ],
   'includes': [
     '../base/base.isolate',
   ],
 }