Allow policy refresh rate to be configured through policy.

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 941 matching lines @@
       'features': {'dynamic_refresh': 0},
       'example_value': False,
       'caption': '''Disable support for 3D graphics APIs''',
       'desc': '''Disable support for 3D graphics APIs.
 
       Enabling this setting prevents web pages from accessing the graphics processing unit (GPU). Specifically, web pages can not access the WebGL API and plugins can not use the Pepper 3D API.
 
       Disabling this setting potentially allows web pages to use the WebGL API and plugins to use the Pepper 3D API. The default settings of the browser may still require command line arguments to be passed in order to use these APIs.''',
     },
     {
+      'name': 'PolicyRefreshRate',
+      'type': 'int',
+      'supported_on': ['chrome_os:1.0.0.0-'],
+      'features': {'dynamic_refresh': 1},
+      'example_value': 3600000,
+      'caption': '''Policy refresh rate''',
+      'desc': '''Specifies the period in milliseconds at which the device management service is queried for policy information.
+
+      Setting this policy overrides the default value of 3 hours. Valid values for this policy are in the range from 30 minutes to 1 day. Any values not in this range will be clamped to the respective boundary.''',
+    },
+    {
       'name': 'ChromeFrameRendererSettings',
       'type': 'group',
       'caption': '''Default HTML renderer for <ph name="PRODUCT_FRAME_NAME">$3<ex>Google Chrome Frame</ex></ph>''',
       'desc': '''Allows you to configure the default HTML renderer when <ph name="PRODUCT_FRAME_NAME">$3<ex>Google Chrome Frame</ex>
       </ph> is installed.
       The default setting is to allow the host browser do the rendering, but you
       can optionally override this and have <ph name="PRODUCT_FRAME_NAME">$3<ex>
       Google Chrome Frame</ex></ph> render HTML pages by default.''',
       'policies': [
         {
@@ skipping 174 matching lines @@
     {
       'key': '$4',
       'value': 'http://www.chromium.org/developers/how-tos/chrome-frame-getting-started'
     },
     {
       'key': '$5',
       'value': 'http://www.chromium.org/administrators/policy-templates'
     },
   ]
 }