Whitelist data savings prefs for the reduction proxy.

chrome/common/extensions/api/preferences_private.json

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
   {
     "namespace": "preferencesPrivate",
     "description": "none",
     "properties": {
       "googleGeolocationAccessEnabled": {
         "nocompile": true,
         "$ref": "types.private.ChromeDirectSetting",
         "value": ["googlegeolocationaccess.enabled", {"type":"boolean"}],
         "description": "If enabled, Google services can access the user's location. This preference's value is a boolean, defaulting to <code>false</code>."
       },
       "spdyProxyEnabled": {
         "nocompile": true,
         "$ref": "types.private.ChromeDirectSetting",
         "value": ["spdy_proxy.enabled", {"type":"boolean"}],
         "description": "Flag to enable data usage reduction by sending requests via data reduction proxy. This preference's value is a boolean, defaulting to <code>false</code>."
+      },
+      "dataReductionDailyContentLength": {
+        "nocompile": true,
+        "$ref": "types.private.ChromeDirectSetting",
+        "value": ["data_reduction.daily_original_length", {"type":"array"}],
+        "description": "Each item contains the number uncompressed bytes through data reduction proxy per day."
+      },
+      "dataReductionDailyReceivedLength": {
+        "nocompile": true,
+        "$ref": "types.private.ChromeDirectSetting",
+        "value": ["data_reduction.daily_received_length", {"type":"array"}],
+        "description": "Each item contains the number of compressed bytes through data reduction proxy per day."
+      },
+      "dataReductionUpdateDailyLengths": {
+        "nocompile": true,
+        "$ref": "types.private.ChromeDirectSetting",
+        "value": ["data_reduction.update_daily_lengths", {"type":"boolean"}],
+        "description": "Flag to indicate that dataReductionDailyContentLength and dataReductionDailyReceivedLength must be updated with their latest values. This preference's value is a boolean, defaulting to <code>false</code>."
       }
     },
     "functions": [
       {
         "name": "getSyncCategoriesWithoutPassphrase",
         "description": "Returns a list of sync categories the user has enabled without using a custom passphrase for encryption. The possible values are those that can be returned from syncer::ModelTypeToString in sync/syncable/model_type.cc.",
         "type": "function",
         "parameters": [
           {
             "name": "callback",
             "type": "function",
             "parameters": [
               {
                 "name": "categories",
                 "type": "array",
                 "items": {"type": "string"}
               }
             ]
           }
         ]
       }
     ]
   }
 ]