Add an API to get total size of Drive cache including non-evictable ones.

components/drive/chromeos/file_system.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_DRIVE_CHROMEOS_FILE_SYSTEM_H_
 #define COMPONENTS_DRIVE_CHROMEOS_FILE_SYSTEM_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 147 matching lines @@
   void SetProperty(const base::FilePath& drive_file_path,
                    google_apis::drive::Property::Visibility visibility,
                    const std::string& key,
                    const std::string& value,
                    const FileOperationCallback& callback) override;
   void Reset(const FileOperationCallback& callback) override;
   void GetPathFromResourceId(const std::string& resource_id,
                              const GetFilePathCallback& callback) override;
   void FreeDiskSpaceIfNeededFor(int64_t num_bytes,
                                 const FreeDiskSpaceCallback& callback) override;
-  void CalculateEvictableCacheSize(
-      const EvictableCacheSizeCallback& callback) override;
+  void CalculateCacheSize(const CacheSizeCallback& callback) override;
+  void CalculateEvictableCacheSize(const CacheSizeCallback& callback) override;
 
   // file_system::OperationDelegate overrides.
   void OnFileChangedByOperation(const FileChange& changed_files) override;
   void OnEntryUpdatedByOperation(const ClientContext& context,
                                  const std::string& local_id) override;
   void OnDriveSyncError(file_system::DriveSyncErrorType type,
                         const std::string& local_id) override;
   bool WaitForSyncComplete(const std::string& local_id,
                            const FileOperationCallback& callback) override;
 
@@ skipping 126 matching lines @@
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate the weak pointers before any other members are destroyed.
   base::WeakPtrFactory<FileSystem> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FileSystem);
 };
 
 }  // namespace drive
 
 #endif  // COMPONENTS_DRIVE_CHROMEOS_FILE_SYSTEM_H_