Add a policy to disable mounting of external storage.

chrome/test/functional/policy_test_cases.py

 #!/usr/bin/env python
 # 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.
 
 # This data is in a separate file so that src/chrome/app/policy/PRESUBMIT.py
 # can load it too without having to load pyautolib.
 
 # DO NOT import pyauto from here! This file is required to run a presubmit
 # scripts that will always fail if pyautolib isn't available, which is common.
@@ skipping 243 matching lines @@
     # TODO(frankf): Add prefs for these after crosbug.com/28756 is fixed.
     'ChromeOsLockOnIdleSuspend':
         (None, True, [BROWSER], ['chromeos']),
     'PolicyRefreshRate':
         (None, 300000, [], ['chromeos']),
     'OpenNetworkConfiguration': (None, '', [], ['chromeos']),
     'GDataDisabled': (None, True, [], ['chromeos']),
     'GDataDisabledOverCellular':
         (None, True, [], ['chromeos']),
     'PinnedLauncherApps': (None, [], [], ['chromeos']),
+    'ExternalStorageDisabled': (None, True, [], ['chromeos']),
 
     # ChromeOS Device policies:
     'DevicePolicyRefreshRate': (None, 300000, [], ['chromeos']),
     'ChromeOsReleaseChannel': (None, 'stable-channel', [], ['chromeos']),
     'ChromeOsReleaseChannelDelegated': (None, False, [], ['chromeos']),
     'DeviceOpenNetworkConfiguration': (None, '', [], ['chromeos']),
     'ReportDeviceVersionInfo': (None, True, [], ['chromeos']),
     'ReportDeviceActivityTimes': (None, True, [], ['chromeos']),
     'ReportDeviceBootMode': (None, True, [], ['chromeos']),
     'DeviceAllowNewUsers': (None, True, [], ['chromeos']),
@@ skipping 17 matching lines @@
     'ReportDeviceLocation': (None, False, [], ['chromeos']),
 
     # Chrome Frame policies:
     'ChromeFrameRendererSettings': (None, 0, [], []),
     'RenderInChromeFrameList': (None, ['google.com'], [], []),
     'RenderInHostList': (None, ['google.com'], [], []),
     'ChromeFrameContentTypes': (None, ['text/xml'], [], []),
     'GCFUserDataDir': (None, '${user_name}/test-frame', [], []),
     'AdditionalLaunchParameters': (None, '--enable-media-stream', [], []),
   }