Add CloudExternalDataPolicyObserverChromeOS

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 13 matching lines @@
 #   'int' - an integer value
 #   'int-enum' - the user can select an integer value from a collection of
 #     items
 #   'string-enum' - the user can select a string value from a collection of
 #     items
 #   'main' - a boolean value
 #   'list' - a list of string values
 #   'dict' - a dictionary value, containing other values indexed by strings
 #     NOTE: This type is not supported yet. http://crbug.com/108992
 #   'external' - a policy that references external data.
-#     NOTE: This type is not supported yet. http://crbug.com/256635
 #
 # Policy group descriptions, policy captions and similar texts are localized
 # strings taken from the <message> nodes of the .grd file. Their name
 # attributes are generated from the JSON keys.
 # Each item (policy or group) may have the following messages:
 #   - description:
 #     Describes the item it applies to.
 #   - caption
 #     A short, one-line summary of the item it applies to. This can appear
 #     both in policy or group listings or on title bars of policy-setting
@@ skipping 66 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: 248
+#   For your editing convenience: highest ID currently used: 249
 #
 # 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 5588 matching lines @@
       },
       'example_value': True,
       'id': 241,
       'caption': '''Enable the data compression proxy feature''',
       'desc': '''Enable or disable the data compression proxy and prevents users from changing this setting.
 
       If you enable or disable this setting, users cannot change or override this setting.
 
       If this policy is left not set, the data compression proxy feature will be available for the user to choose whether to use it or not.''',
     },
+    {
+      'name': 'Avatar',

[Joao da Silva, 2013/11/27 14:33:59]

I find the name a bit too generic, maybe 'UserAvatarImage'?

[bartfab (slow), 2013/11/27 20:10:15]

Done.

+      'type': 'external',

[Joao da Silva, 2013/11/27 14:33:59]

You'll probably have to update & roll grit to support this.

Can you build target policy_templates with this policy in the templates?

[bartfab (slow), 2013/11/27 20:10:15]

Done: https://codereview.chromium.org/92213002

+      'schema': {
+        'type': 'object',
+        'properties': {
+          'url': { "type": "string" },
+          'hash': { "type": "string" }
+        },
+      },
+      'supported_on': ['chrome_os:33-'],
+      'features': {
+        'dynamic_refresh': True,
+        'per_profile': True,
+      },
+      'example_value': { "url": "http://example.com/avatar.jpg", "hash": "deadbeefdeadbeefdeadbeefdeadbeef" },
+      'max_size': 524288,
+      'id': 249,
+      'caption': '''Avatar image''',
+      'desc': '''Configure avatar image.
+
+      This policy allows you to configure the avatar image representing the user on the login screen. The policy is set by specifying the URL from which <ph name="PRODUCT_OS_NAME">$2<ex>Google Chrome OS</ex></ph> can download the avatar image and a cryptographic hash used to verify the integrity of the download. The image must be in JPEG format, its size must not exceed 512kB. The URL must be accessible without any authentication.

[Joao da Silva, 2013/11/27 14:33:59]

The hash is also used to determine if the picture has been updated.

[bartfab (slow), 2013/11/27 20:10:15]

Done.

+
+      The policy should be specified as a string that expresses the URL and hash in JSON format, conforming to the following schema:
+      {
+        "type": "object",
+        "properties": {
+          "url": {
+            "description": "The URL from which the avatar image can be downloaded.",
+            "type": "string",

[Joao da Silva, 2013/11/27 14:33:59]

JSON doesn't allow trailing commas

[bartfab (slow), 2013/11/27 20:10:15]

Trailing comma is best comma.

+          },
+          "hash": {
+            "description": "The SHA-1 hash of the avatar image.",
+            "type": "string",
+          }
+        }
+      }
+
+      If this policy is set, <ph name="PRODUCT_OS_NAME">$2<ex>Google Chrome OS</ex></ph> will download and use the avatar image.
+
+      If you set this policy, users cannot change or override it.
+
+      If the policy is left not set, the user can choose the avatar image representing him/her on the login screen.''',
+    },
   ],
   '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 84 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': 'Default Settings (users can override)',
     },
   },
   'placeholders': [],
 }