Add flags for CrOS Component using Feature API

chrome/browser/about_flags.cc

 // 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.
 
 #include "chrome/browser/about_flags.h"
 
 #include <iterator>
 #include <map>
 #include <set>
 #include <utility>
@@ skipping 2285 matching lines @@
      FEATURE_VALUE_TYPE(features::kOptInImeMenu)},
     {"disable-system-timezone-automatic-detection",
      flag_descriptions::kDisableSystemTimezoneAutomaticDetectionName,
      flag_descriptions::kDisableSystemTimezoneAutomaticDetectionDescription,
      kOsCrOS,
      SINGLE_VALUE_TYPE(
          chromeos::switches::kDisableSystemTimezoneAutomaticDetectionPolicy)},
     {"disable-native-cups", flag_descriptions::kDisableNativeCupsName,
      flag_descriptions::kDisableNativeCupsDescription, kOsCrOS,
      SINGLE_VALUE_TYPE(switches::kDisableNativeCups)},
+    {"cros-component", flag_descriptions::kCrOSComponentName,

[skau, 2017/05/03 21:07:49]

You want this to say enable-cros-component so it's easy to tell what the default
state is.

[xiaochu, 2017/05/03 23:40:28]

Done.

+     flag_descriptions::kCrOSComponentDescription, kOsCrOS,
+     FEATURE_VALUE_TYPE(features::kCrOSComponent)},
     {"enable-encryption-migration",
      flag_descriptions::kEnableEncryptionMigrationName,
      flag_descriptions::kEnableEncryptionMigrationDescription, kOsCrOS,
      ENABLE_DISABLE_VALUE_TYPE(
          chromeos::switches::kEnableEncryptionMigration,
          chromeos::switches::kDisableEncryptionMigration)},
 #endif  // OS_CHROMEOS
 #if !defined(OS_ANDROID) && !defined(OS_IOS) && defined(GOOGLE_CHROME_BUILD)
     {"enable-google-branded-context-menu",
      flag_descriptions::kGoogleBrandedContextMenuName,
@@ skipping 688 matching lines @@
 const base::HistogramBase::Sample kBadSwitchFormatHistogramId = 0;
 
 const FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags