Stop forcing optional permission on usbDevices section

chrome/common/extensions/permissions/chrome_api_permissions.cc

 // Copyright (c) 2013 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/common/extensions/permissions/chrome_api_permissions.h"
 
 #include "chrome/common/extensions/permissions/api_permission.h"
 #include "chrome/common/extensions/permissions/api_permission_set.h"
 #include "chrome/common/extensions/permissions/bluetooth_device_permission.h"
 #include "chrome/common/extensions/permissions/media_galleries_permission.h"
@@ skipping 233 matching lines @@
     { APIPermission::kBluetooth, "bluetooth", APIPermissionInfo::kFlagNone,
       IDS_EXTENSION_PROMPT_WARNING_BLUETOOTH,
       PermissionMessage::kBluetooth },
     { APIPermission::kBluetoothDevice, "bluetoothDevices",
       APIPermissionInfo::kFlagNone, 0, PermissionMessage::kNone,
       &CreateAPIPermission<BluetoothDevicePermission> },
     { APIPermission::kUsb, "usb", APIPermissionInfo::kFlagNone,
       IDS_EXTENSION_PROMPT_WARNING_USB,
       PermissionMessage::kUsb },
     { APIPermission::kUsbDevice, "usbDevices",
-      APIPermissionInfo::kFlagMustBeOptional, 0, PermissionMessage::kNone,
+      APIPermissionInfo::kFlagNone, 0, PermissionMessage::kNone,
       &CreateAPIPermission<UsbDevicePermission> },
     { APIPermission::kSystemIndicator, "systemIndicator",
       APIPermissionInfo::kFlagNone,
       IDS_EXTENSION_PROMPT_WARNING_SYSTEM_INDICATOR,
       PermissionMessage::kSystemIndicator },
     { APIPermission::kSystemInfoDisplay, "systemInfo.display" },
     { APIPermission::kPointerLock, "pointerLock" },
     { APIPermission::kFullscreen, "fullscreen" },
     { APIPermission::kAudio, "audio" },
   };
@@ skipping 16 matching lines @@
   // Register aliases.
   std::vector<PermissionsInfo::AliasInfo> aliases;
   aliases.push_back(PermissionsInfo::AliasInfo(
       "unlimitedStorage", kOldUnlimitedStoragePermission));
   aliases.push_back(PermissionsInfo::AliasInfo(
       "tabs", kWindowsPermission));
   return aliases;
 }
 
 }  // namespace extensions