Remove UserPolicyDiskCache; it is not used.

chrome/browser/chromeos/policy/user_policy_disk_cache.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_POLICY_DISK_CACHE_H_
-#define CHROME_BROWSER_CHROMEOS_POLICY_USER_POLICY_DISK_CACHE_H_
-
-#include "base/files/file_path.h"
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
-
-namespace base {
-class SequencedTaskRunner;
-}
-
-namespace enterprise_management {
-class CachedCloudPolicyResponse;
-}
-
-namespace policy {
-
-// Handles the on-disk cache file used by UserPolicyCache. This class handles
-// the necessary thread switching and may outlive the associated UserPolicyCache
-// instance.
-class UserPolicyDiskCache
-    : public base::RefCountedThreadSafe<UserPolicyDiskCache> {
- public:
-  // Indicates the status of a completed load operation.
-  enum LoadResult {
-    // Policy was loaded successfully.
-    LOAD_RESULT_SUCCESS,
-    // Cache file missing.
-    LOAD_RESULT_NOT_FOUND,
-    // Failed to read cache file.
-    LOAD_RESULT_READ_ERROR,
-    // Failed to parse cache file.
-    LOAD_RESULT_PARSE_ERROR,
-  };
-
-  // Delegate interface for observing loads operations.
-  class Delegate {
-   public:
-    virtual ~Delegate();
-    virtual void OnDiskCacheLoaded(
-        LoadResult result,
-        const enterprise_management::CachedCloudPolicyResponse& policy) = 0;
-  };
-
-  UserPolicyDiskCache(
-      const base::WeakPtr<Delegate>& delegate,
-      const base::FilePath& backing_file_path,
-      scoped_refptr<base::SequencedTaskRunner> background_task_runner);
-
-  // Starts reading the policy cache from disk. Passes the read policy
-  // information back to the hosting UserPolicyCache after a successful cache
-  // load through UserPolicyCache::OnDiskCacheLoaded().
-  void Load();
-
-  // Triggers a write operation to the disk cache on the FILE thread.
-  void Store(const enterprise_management::CachedCloudPolicyResponse& policy);
-
- private:
-  friend class base::RefCountedThreadSafe<UserPolicyDiskCache>;
-  ~UserPolicyDiskCache();
-
-  // Tries to load the cache file on the FILE thread.
-  void LoadOnFileThread();
-
-  // Forwards the result to the UI thread.
-  void LoadDone(LoadResult result,
-                const enterprise_management::CachedCloudPolicyResponse& policy);
-
-  // Passes back the successfully read policy to the cache on the UI thread.
-  void ReportResultOnUIThread(
-      LoadResult result,
-      const enterprise_management::CachedCloudPolicyResponse& policy);
-
-  // Saves a policy blob on the FILE thread.
-  void StoreOnFileThread(
-      const enterprise_management::CachedCloudPolicyResponse& policy);
-
-  base::WeakPtr<Delegate> delegate_;
-  const base::FilePath backing_file_path_;
-  scoped_refptr<base::SequencedTaskRunner> origin_task_runner_;
-  scoped_refptr<base::SequencedTaskRunner> background_task_runner_;
-
-  DISALLOW_COPY_AND_ASSIGN(UserPolicyDiskCache);
-};
-
-}  // namespace policy
-
-#endif  // CHROME_BROWSER_CHROMEOS_POLICY_USER_POLICY_DISK_CACHE_H_