Add --windows10-custom-titlebar to the about:flags page.

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 2185 matching lines @@
      IDS_FLAGS_ENABLE_EXPANDED_AUTOFILL_CREDIT_CARD_POPUP_LAYOUT,
      IDS_FLAGS_ENABLE_EXPANDED_AUTOFILL_CREDIT_CARD_POPUP_LAYOUT_DESCRIPTION,
      kOsAndroid, FEATURE_WITH_VARIATIONS_VALUE_TYPE(
                      autofill::kAutofillCreditCardPopupLayout,
                      kAutofillCreditCardPopupLayoutFeatureVariations,
                      "AutofillCreditCardPopupLayout")},
     {"native-android-history-manager", IDS_NATIVE_ANDROID_HISTORY_MANAGER,
      IDS_NATIVE_ANDROID_HISTORY_MANAGER_DESCRIPTION, kOsAndroid,
      FEATURE_VALUE_TYPE(chrome::android::kNativeAndroidHistoryManager)},
 #endif  // OS_ANDROID
+
+#if defined(OS_WIN)
+    {"windows10-custom-titlebar", IDS_FLAGS_WINDOWS10_CUSTOM_TITLEBAR_NAME,
+     IDS_FLAGS_WINDOWS10_CUSTOM_TITLEBAR_DESCRIPTION, kOsWin,
+     SINGLE_VALUE_TYPE(switches::kWindows10CustomTitlebar)},
+#endif  // OS_WIN
+
     {"enable-faster-location-reload", IDS_FLAGS_FASTER_LOCATION_RELOAD_NAME,
      IDS_FLAGS_FASTER_LOCATION_RELOAD_DESCRIPTION, kOsAll,
      FEATURE_VALUE_TYPE(features::kFasterLocationReload)},
 #if defined(OS_ANDROID)
     {"lsd-permission-prompt", IDS_FLAGS_LSD_PERMISSION_PROMPT_NAME,
      IDS_FLAGS_LSD_PERMISSION_PROMPT_DESCRIPTION, kOsAndroid,
      FEATURE_VALUE_TYPE(features::kLsdPermissionPrompt)},
 #endif
 
 #if defined(OS_CHROMEOS)
@@ skipping 203 matching lines @@
 const base::HistogramBase::Sample kBadSwitchFormatHistogramId = 0;
 
 const FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags