Add policies to control power management on the Chrome OS login screen

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: 223
+#   For your editing convenience: highest ID currently used: 224
 #
 # 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 4360 matching lines @@
 
           If this policy is set, it specifies the percentage by which the screen dim delay is scaled when user activity is observed while the screen is dimmed or soon after the screen has been turned off. When the dim delay is scaled, the screen off, screen lock and idle delays get adjusted to maintain the same distances from the screen dim delay as originally configured.
 
           If this policy is unset, a default scale factor is used.
 
           The scale factor must be 100% or more.''',
         },
       ],
     },
     {
+      'name': 'DeviceLoginScreenPowerManagement',
+      'type': 'string',
+      'schema': { 'type': 'string' },
+      'supported_on': ['chrome_os:30-'],
+      'device_only': True,
+      'features': {
+        'dynamic_refresh': True,
+      },
+      'example_value': '{ "AC": { "IdleAction": 3 }, "Battery": { "IdleAction": 3 } }',
+      'id': 224,
+      'caption': '''Power mangement on the login screen''',
+      'desc': '''Configure power management on the login screen in <ph name="PRODUCT_OS_NAME">$2<ex>Google Chrome OS</ex></ph>.
+
+      This policy lets you configure how <ph name="PRODUCT_OS_NAME">$2<ex>Google Chrome OS</ex></ph> behaves when there is no user activity for some amount of time while the login screen is being shown. The policy controls multiple settings. For their individual semantics and value ranges, see the corresponding policies that control power management within a session. The only deviations from these policies are:

[Mattias Nissler (ping if slow), 2013/07/08 17:36:57]

Are we planning on redoing the session power policies to be a dictionary as
well? If so, you'll have to write a full description eventually ;)

[bartfab (slow), 2013/07/09 10:02:33]

Yes, at that point, I will just consolidate the descriptions of the individual
policies into a single description. For now, we need to keep the individual
policies documented. I do not think that duplicating the documentation here
would be very useful.

+      * The actions to take on idle or lid close cannot be to end the session.
+      * The default action taken on idle when running on AC power is to shut down.
+
+      The policy should be specified as a string that expresses the individual settings in JSON format, conforming to the following schema:

[Mattias Nissler (ping if slow), 2013/07/08 17:36:57]

Did you check with Joao what the story is on dictionary-valued policy? I assume
the plan is to go with string for now and switch over to a proper schema here
once end-to-end support for dictionary types becomes available?

It might be helpful to add a TODO here providing some context.

[bartfab (slow), 2013/07/09 10:02:33]

I added a TODO. And yes, I had checked with Joao. His recommendation is to go
with 'string' for now. Once 'dict' is fully supported, it will be trivial to
switch to that as the cloud wire protocol will remain the same - a 'dict' will
still be expressed as a JSON string in the protobuf.

+      {
+        "type": "object",
+        "properties": {
+          "AC": {
+            "type": "object",
+            "properties": {
+              "Delays": {
+                "type": "object",
+                "properties": {
+                  "ScreenDim": {
+                    "type": "integer",
+                    "minimum": 0
+                  },
+                  "ScreenOff": {
+                    "type": "integer",
+                    "minimum": 0
+                  },
+                  "Idle": {
+                    "type": "integer",
+                    "minimum": 0
+                  }
+                }
+              },
+              "IdleAction": {
+                "enum": [ 0, 2, 3 ]

[Mattias Nissler (ping if slow), 2013/07/08 17:36:57]

This seems unfortunate. Can we do a string enum instead?

[bartfab (slow), 2013/07/09 10:02:33]

Done.

+              }
+            }
+          },
+          "Battery": {
+            "type": "object",
+            "properties": {
+              "Delays": {
+                "type": "object",
+                "properties": {
+                  "ScreenDim": {
+                    "type": "integer",
+                    "minimum": 0
+                  },
+                  "ScreenOff": {
+                    "type": "integer",
+                    "minimum": 0
+                  },
+                  "Idle": {
+                    "type": "integer",
+                    "minimum": 0
+                  }
+                }
+              },
+              "IdleAction": {
+                "enum": [ 0, 2, 3 ]

[Mattias Nissler (ping if slow), 2013/07/08 17:36:57]

ditto

[bartfab (slow), 2013/07/09 10:02:33]

Done.

+              }
+            }
+          },
+          "LidCloseAction": {
+            "enum": [ 0, 2, 3 ]

[Mattias Nissler (ping if slow), 2013/07/08 17:36:57]

ditto

[bartfab (slow), 2013/07/09 10:02:33]

Done.

+          },
+          "UserActivityScreenDimDelayScale": {
+            "type": "integer",
+            "minimum": 0
+          }
+        }
+      }
+
+      If a setting is left unspecified, a default value is used.
+
+      If this policy is unset, defaults are used for all settings.''',
+    },
+    {
       'name': 'DeviceAllowRedeemChromeOsRegistrationOffers',
       'type': 'main',
       'schema': { 'type': 'boolean' },
       'supported_on': ['chrome_os:26-'],
       'device_only': True,
       'features': {
         'dynamic_refresh': True,
       },
       'example_value': True,
       'id': 185,
@@ skipping 682 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': [],
 }