Allow policy refresh rate to be configured through policy.

chrome/app/policy/policy_templates.json

Index: chrome/app/policy/policy_templates.json
diff --git a/chrome/app/policy/policy_templates.json b/chrome/app/policy/policy_templates.json
index d046bf961c33434ee74dbe21e4db0cfb12f19ec5..01b1ee4d51b48007cf5ce307f49245bf951827e9 100644
--- a/chrome/app/policy/policy_templates.json
+++ b/chrome/app/policy/policy_templates.json
@@ -959,6 +959,17 @@
       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>''',