Convert the overlay scrollbar flag to use FeatureList

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index f5e8f573463fd4bb247028ed8c07f58643cb8223..69d29f3630a7ba8d2efe31e8a99999109e6a0f8c 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -95,7 +95,7 @@
 #include "ui/gl/gl_features.h"
 #include "ui/gl/gl_switches.h"
 #include "ui/keyboard/keyboard_switches.h"
-#include "ui/native_theme/native_theme_switches.h"
+#include "ui/native_theme/native_theme_features.h"
 #include "ui/views/views_switches.h"
 
 #if defined(OS_ANDROID)
@@ -991,9 +991,7 @@ const FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kOverlayScrollbarsDescription,
      // Uses the system preference on Mac (a different implementation).
      // On Android, this is always enabled.
-     kOsAura,
-     ENABLE_DISABLE_VALUE_TYPE(switches::kEnableOverlayScrollbar,
-                               switches::kDisableOverlayScrollbar)},
+     kOsAura, FEATURE_VALUE_TYPE(features::kOverlayScrollbar)},
 #endif  // USE_AURA
     {   // See http://crbug.com/120416 for how to remove this flag.
      "save-page-as-mhtml", flag_descriptions::kSavePageAsMhtmlName,
@@ -2608,10 +2606,8 @@ const FeatureEntry kFeatureEntries[] = {
 #if defined(OS_CHROMEOS)
     {"enable-zip-archiver-on-file-manager",
      flag_descriptions::kEnableZipArchiverOnFileManagerName,
-     flag_descriptions::kEnableZipArchiverOnFileManagerDescription,
-     kOsCrOS,
-     SINGLE_VALUE_TYPE(
-         chromeos::switches::kEnableZipArchiverOnFileManager)},
+     flag_descriptions::kEnableZipArchiverOnFileManagerDescription, kOsCrOS,
+     SINGLE_VALUE_TYPE(chromeos::switches::kEnableZipArchiverOnFileManager)},
 #endif  // OS_CHROMEOS
 
 #if defined(OS_ANDROID)