Added a timezone policy and pyauto tests for it.

chrome/app/policy/policy_templates.json

 {
 # policy_templates.json - Metafile for policy templates
 #
 # The content of this file is evaluated as a Python expression.
 #
 # This file is used as input to generate the following policy templates:
 # ADM, ADMX+ADML, MCX/plist and html documentation.
 #
 # Policy templates are user interface definitions or documents about the
 # policies that can be used to configure Chrome. Each policy is a name-value
@@ skipping 94 matching lines @@
 #   templates and documentation. The policy definition list that Chrome sees
 #   will include policies marked with 'future'. If a WIP policy isn't meant to
 #   be seen by the policy providers either, the 'supported_on' key should be set
 #   to an empty list.
 #
 # IDs:
 #   Since a Protocol Buffer definition is generated from this file, unique and
 #   persistent IDs for all fields (but not for groups!) are needed. These are
 #   specified by the 'id' keys of each policy. NEVER CHANGE EXISTING IDs,
 #   because doing so would break the deployed wire format!
-#   For your editing convenience: highest ID currently used: 156
+#   For your editing convenience: highest ID currently used: 157
 #
 # Placeholders:
 #   The following placeholder strings are automatically substituted:
 #     $1 -> Google Chrome / Chromium
 #     $2 -> Google Chrome OS / Chromium OS
 #     $3 -> Google Chrome Frame / Chromium Frame
 #     $6 is reserved for doc_writer
 #
 # Device Policy:
 #   An additional flag device_only (optional, defaults to False) indicates
@@ skipping 3017 matching lines @@
       },
       'example_value': True,
       'id': 153,
       'caption': '''Disable taking screenshots''',
       'desc': '''Disables taking screenshots.
 
       If enabled screenshots cannot be taken using keyboard shortcuts or extension APIs.
 
       If disabled or not specified, taking screenshots is allowed.'''
     },
+    {
+      'name': 'DeviceTimezone',
+      'type': 'string',
+      'schema': { 'type': 'string' },
+      'supported_on': ['chrome_os:22-'],
+      'device_only': True,
+      'features': {'dynamic_refresh': True},
+      'example_value': 'America/Los_Angeles',
+      'id': 157,
+      'caption': '''Timezone''',
+      'desc': '''Specifies the timezone to be used for the device. Users can override the specified timezone for the current session.
+      However, on logout it is set back to the specified timezone.
+
+      If this policy is not used or set to an invalid value, users can change the timezone and the change is persistent. Thus a change affects the login-screen and other users.
+      If additionally no user ever set a timezone, a default value (currently "US/Pacific") is used.''',
+    },
   ],
   'messages': {
     # Messages that are not associated to any policies.
     'win_supported_winxpsp2': {
       'desc': '''A label specifying the oldest possible compatible version of Windows. This text will appear right next to a label containing the text 'Supported on:'.''',
       'text': '''Microsoft Windows XP SP2 or later'''
     },
     'mac_chrome_preferences': {
       'desc': '''A text indicating in Mac OS X Workgroup Manager, that currently the preferences of Chrome are being edited''',
       'text': '''<ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> preferences'''
@@ skipping 78 matching lines @@
       'desc': '''Text appended in parentheses to the policy name to indicate that it has been deprecated''',
       'text': 'deprecated',
     },
     'doc_recommended': {
       'desc': '''Text appended in parentheses next to the policies top-level container to indicate that those policies are of the Recommended level''',
       'text': 'Recommended',
     },
   },
   'placeholders': [],
 }