Expose signing key from cloud policy stores

chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos.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 CHROME_BROWSER_CHROMEOS_POLICY_USER_CLOUD_POLICY_STORE_CHROMEOS_H_
 #define CHROME_BROWSER_CHROMEOS_POLICY_USER_CLOUD_POLICY_STORE_CHROMEOS_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 83 matching lines @@
                               const std::string& sanitized_username);
 
   std::unique_ptr<UserCloudPolicyValidator> CreateValidatorForLoad(
       std::unique_ptr<enterprise_management::PolicyFetchResponse> policy);
 
   chromeos::CryptohomeClient* cryptohome_client_;
   chromeos::SessionManagerClient* session_manager_client_;
   const AccountId account_id_;
   base::FilePath user_policy_key_dir_;
 
-  bool policy_key_loaded_;
-  base::FilePath policy_key_path_;
-  std::string policy_key_;
+  // The current key used to verify signatures of policy. This value is loaded
+  // from the key cache file (which is owned and kept up to date by the Chrome
+  // OS session manager). This is, generally, different from
+  // |policy_signature_public_key_|, which always corresponds to the currently
+  // effective policy.
+  std::string cached_policy_key_;
+  bool cached_policy_key_loaded_ = false;
+  base::FilePath cached_policy_key_path_;
 
   base::WeakPtrFactory<UserCloudPolicyStoreChromeOS> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(UserCloudPolicyStoreChromeOS);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_CHROMEOS_POLICY_USER_CLOUD_POLICY_STORE_CHROMEOS_H_