Fix EnterpriseDeviceManagementStatus UMA enum, add comments.

components/policy/core/common/cloud/cloud_policy_constants.h

 // Copyright (c) 2012 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.
 
 #ifndef COMPONENTS_POLICY_CORE_COMMON_CLOUD_CLOUD_POLICY_CONSTANTS_H_
 #define COMPONENTS_POLICY_CORE_COMMON_CLOUD_CLOUD_POLICY_CONSTANTS_H_
 
 #include <string>
 #include <utility>
 
@@ skipping 51 matching lines @@
 
 // Describes the affiliation of a user w.r.t. the device owner.
 enum UserAffiliation {
   // User is on the same domain the device was registered with.
   USER_AFFILIATION_MANAGED,
   // No affiliation between device and user.
   USER_AFFILIATION_NONE,
 };
 
 // Status codes for communication errors with the device management service.
+// This enum is used to define the buckets for an enumerated UMA histogram.
+// Hence,
+//   (a) existing enumerated constants should never be deleted or reordered, and
+//   (b) new constants should only be appended at the end of the enumeration.
 enum DeviceManagementStatus {
   // All is good.
-  DM_STATUS_SUCCESS,
+  DM_STATUS_SUCCESS = 0,
   // Request payload invalid.
-  DM_STATUS_REQUEST_INVALID,
+  DM_STATUS_REQUEST_INVALID = 1,
   // The HTTP request failed.
-  DM_STATUS_REQUEST_FAILED,
+  DM_STATUS_REQUEST_FAILED = 2,
   // The server returned an error code that points to a temporary problem.
-  DM_STATUS_TEMPORARY_UNAVAILABLE,
+  DM_STATUS_TEMPORARY_UNAVAILABLE = 3,
   // The HTTP request returned a non-success code.
-  DM_STATUS_HTTP_STATUS_ERROR,
+  DM_STATUS_HTTP_STATUS_ERROR = 4,
   // Response could not be decoded.
-  DM_STATUS_RESPONSE_DECODING_ERROR,
+  DM_STATUS_RESPONSE_DECODING_ERROR = 5,
   // Service error: Management not supported.
-  DM_STATUS_SERVICE_MANAGEMENT_NOT_SUPPORTED,
+  DM_STATUS_SERVICE_MANAGEMENT_NOT_SUPPORTED = 6,
   // Service error: Device not found.
-  DM_STATUS_SERVICE_DEVICE_NOT_FOUND,
+  DM_STATUS_SERVICE_DEVICE_NOT_FOUND = 7,
   // Service error: Device token invalid.
-  DM_STATUS_SERVICE_MANAGEMENT_TOKEN_INVALID,
+  DM_STATUS_SERVICE_MANAGEMENT_TOKEN_INVALID = 8,
   // Service error: Activation pending.
-  DM_STATUS_SERVICE_ACTIVATION_PENDING,
+  DM_STATUS_SERVICE_ACTIVATION_PENDING = 9,
   // Service error: The serial number is not valid or not known to the server.
-  DM_STATUS_SERVICE_INVALID_SERIAL_NUMBER,
+  DM_STATUS_SERVICE_INVALID_SERIAL_NUMBER = 10,
   // Service error: The device id used for registration is already taken.
-  DM_STATUS_SERVICE_DEVICE_ID_CONFLICT,
+  DM_STATUS_SERVICE_DEVICE_ID_CONFLICT = 11,
   // Service error: The licenses have expired or have been exhausted.
-  DM_STATUS_SERVICE_MISSING_LICENSES,
+  DM_STATUS_SERVICE_MISSING_LICENSES = 12,
   // Service error: The administrator has deprovisioned this client.
-  DM_STATUS_SERVICE_DEPROVISIONED,
+  DM_STATUS_SERVICE_DEPROVISIONED = 13,
   // Service error: Device registration for the wrong domain.
-  DM_STATUS_SERVICE_DOMAIN_MISMATCH,
+  DM_STATUS_SERVICE_DOMAIN_MISMATCH = 14,
   // Service error: Policy not found. Error code defined by the DM folks.
   DM_STATUS_SERVICE_POLICY_NOT_FOUND = 902,
 };
 
 // List of modes that the device can be locked into.
 enum DeviceMode {
   DEVICE_MODE_PENDING,         // The device mode is not yet available.
   DEVICE_MODE_NOT_SET,         // The device is not yet enrolled or owned.
   DEVICE_MODE_CONSUMER,        // The device is locally owned as consumer
                                // device.
@@ skipping 10 matching lines @@
 
 // Returns the Chrome user policy type to use. This allows overridding the
 // default user policy type on Android and iOS for testing purposes.
 // TODO(joaodasilva): remove this once the server is ready.
 // http://crbug.com/248527
 POLICY_EXPORT const char* GetChromeUserPolicyType();
 
 }  // namespace policy
 
 #endif  // COMPONENTS_POLICY_CORE_COMMON_CLOUD_CLOUD_POLICY_CONSTANTS_H_