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

components/drive/chromeos/file_system_interface.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_INTERFACE_H_
 #define COMPONENTS_DRIVE_CHROMEOS_FILE_SYSTEM_INTERFACE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 130 matching lines @@
     MarkMountedCallback;
 
 // Used to get file path.
 typedef base::Callback<void(FileError error, const base::FilePath& file_path)>
     GetFilePathCallback;
 
 // Used to free space.
 typedef base::Callback<void(bool)> FreeDiskSpaceCallback;
 
 // Used for returning result of calculated cache size.
-typedef base::Callback<void(uint64_t)> EvictableCacheSizeCallback;
+typedef base::Callback<void(int64_t)> CacheSizeCallback;
 
 // The mode of opening a file.
 enum OpenMode {
   // Open the file if exists. If not, failed.
   OPEN_FILE,
 
   // Create a new file if not exists, and then open it. If exists, failed.
   CREATE_FILE,
 
   // Open the file if exists. If not, create a new file and then open it.
@@ skipping 299 matching lines @@
   // Finds a path of an entry (a file or a directory) by |resource_id|.
   virtual void GetPathFromResourceId(const std::string& resource_id,
                                      const GetFilePathCallback& callback) = 0;
 
   // Free drive caches if needed to secure given available spaces. |callback|
   // takes whether given bytes are available or not.
   virtual void FreeDiskSpaceIfNeededFor(
       int64_t num_bytes,
       const FreeDiskSpaceCallback& callback) = 0;
 
+  // Calculates total cache size.
+  // |callback| must not be null.
+  virtual void CalculateCacheSize(const CacheSizeCallback& callback) = 0;
+
   // Calculates evictable cache size.
   // |callback| must not be null.
   virtual void CalculateEvictableCacheSize(
-      const EvictableCacheSizeCallback& callback) = 0;
+      const CacheSizeCallback& callback) = 0;
 };
 
 }  // namespace drive
 
 #endif  // COMPONENTS_DRIVE_CHROMEOS_FILE_SYSTEM_INTERFACE_H_