Fix EnterpriseDeviceManagementStatus UMA enum, add comments.

components/policy/core/common/policy_load_status.h

 // Copyright (c) 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.
 
 #ifndef COMPONENTS_POLICY_CORE_COMMON_POLICY_LOAD_STATUS_H_
 #define COMPONENTS_POLICY_CORE_COMMON_POLICY_LOAD_STATUS_H_
 
 #include <bitset>
 
 #include "base/basictypes.h"
 #include "components/policy/policy_export.h"
 
 namespace base {
 class HistogramBase;
 }
 
 namespace policy {
 
 // UMA histogram enum for policy load status. Don't change existing constants,
 // append additional constants to the end if needed.
 enum PolicyLoadStatus {
   // Policy load attempt started. This gets logged for each policy load attempt
   // to get a baseline on the number of requests, and an arbitrary number of
   // the below status codes may get added in addition.
-  POLICY_LOAD_STATUS_STARTED,
+  POLICY_LOAD_STATUS_STARTED = 0,
   // System failed to determine whether there's policy.
-  POLICY_LOAD_STATUS_QUERY_FAILED,
+  POLICY_LOAD_STATUS_QUERY_FAILED = 1,
   // No policy present.
-  POLICY_LOAD_STATUS_NO_POLICY,
+  POLICY_LOAD_STATUS_NO_POLICY = 2,
   // Data inaccessible, such as non-local policy file.
-  POLICY_LOAD_STATUS_INACCCESSIBLE,
+  POLICY_LOAD_STATUS_INACCCESSIBLE = 3,
   // Data missing, such as policy file not present.
-  POLICY_LOAD_STATUS_MISSING,
+  POLICY_LOAD_STATUS_MISSING = 4,
   // Trying with Wow64 redirection disabled.
-  POLICY_LOAD_STATUS_WOW64_REDIRECTION_DISABLED,
+  POLICY_LOAD_STATUS_WOW64_REDIRECTION_DISABLED = 5,
   // Data read error, for example file reading errors.
-  POLICY_LOAD_STATUS_READ_ERROR,
+  POLICY_LOAD_STATUS_READ_ERROR = 6,
   // Data too large to process.
-  POLICY_LOAD_STATUS_TOO_BIG,
+  POLICY_LOAD_STATUS_TOO_BIG = 7,
   // Parse error.
-  POLICY_LOAD_STATUS_PARSE_ERROR,
+  POLICY_LOAD_STATUS_PARSE_ERROR = 8,
 
   // This must stay last.
   POLICY_LOAD_STATUS_SIZE
 };
 
 // A helper for generating policy load status UMA statistics that'll collect
 // histogram samples for a policy load operation and records histogram samples
 // for the status codes that were seen on destruction.
 class POLICY_EXPORT PolicyLoadStatusSample {
  public:
   PolicyLoadStatusSample();
   ~PolicyLoadStatusSample();
 
   // Adds a status code.
   void Add(PolicyLoadStatus status);
 
  private:
   std::bitset<POLICY_LOAD_STATUS_SIZE> status_bits_;
   base::HistogramBase* histogram_;
 
   DISALLOW_COPY_AND_ASSIGN(PolicyLoadStatusSample);
 };
 
 }  // namespace policy
 
 #endif  // COMPONENTS_POLICY_CORE_COMMON_POLICY_LOAD_STATUS_H_