Use ENABLE_DISABLE_VALUE_TYPE for storage-manager switch and enable it by default on dev.

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 1084 matching lines @@
      IDS_FLAGS_GESTURE_TYPING_DESCRIPTION, kOsCrOS,
      SINGLE_DISABLE_VALUE_TYPE(keyboard::switches::kDisableGestureTyping)},
     {"gesture-editing", IDS_FLAGS_GESTURE_EDITING_NAME,
      IDS_FLAGS_GESTURE_EDITING_DESCRIPTION, kOsCrOS,
      SINGLE_DISABLE_VALUE_TYPE(keyboard::switches::kDisableGestureEditing)},
     {"enable-fullscreen-app-list", IDS_FLAGS_FULLSCREEN_APP_LIST_NAME,
      IDS_FLAGS_FULLSCREEN_APP_LIST_DESCRIPTION, kOsCrOS,
      SINGLE_VALUE_TYPE(ash::switches::kAshEnableFullscreenAppList)},
     {"enable-storage-manager", IDS_FLAGS_STORAGE_MANAGER_NAME,
      IDS_FLAGS_STORAGE_MANAGER_DESCRIPTION, kOsCrOS,
-     SINGLE_VALUE_TYPE(chromeos::switches::kEnableStorageManager)},
+     ENABLE_DISABLE_VALUE_TYPE(chromeos::switches::kEnableStorageManager,
+                               chromeos::switches::kDisableStorageManager)},
 #endif
     {"enable-simple-cache-backend", IDS_FLAGS_SIMPLE_CACHE_BACKEND_NAME,
      IDS_FLAGS_SIMPLE_CACHE_BACKEND_DESCRIPTION,
      kOsWin | kOsMac | kOsLinux | kOsCrOS,
      MULTI_VALUE_TYPE(kSimpleCacheBackendChoices)},
     {"enable-tcp-fast-open", IDS_FLAGS_TCP_FAST_OPEN_NAME,
      IDS_FLAGS_TCP_FAST_OPEN_DESCRIPTION, kOsLinux | kOsCrOS | kOsAndroid,
      SINGLE_VALUE_TYPE(switches::kEnableTcpFastOpen)},
 #if defined(ENABLE_SERVICE_DISCOVERY)
     {"device-discovery-notifications",
@@ skipping 990 matching lines @@
 const base::HistogramBase::Sample kBadSwitchFormatHistogramId = 0;
 
 const FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags