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

components/drive/chromeos/file_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 COMPONENTS_DRIVE_CHROMEOS_FILE_CACHE_H_
 #define COMPONENTS_DRIVE_CHROMEOS_FILE_CACHE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 75 matching lines @@
   //
   // Can be called on any thread.
   bool IsUnderFileCacheDirectory(const base::FilePath& path) const;
 
   // Frees up disk space to store a file with |num_bytes| size content, while
   // keeping drive::internal::kMinFreeSpaceInBytes bytes on the disk, if needed.
   // Returns true if we successfully manage to have enough space, otherwise
   // false.
   bool FreeDiskSpaceIfNeededFor(int64_t num_bytes);
 
+  // Calculates and returns cache size. In error case, this returns 0.
+  int64_t CalculateCacheSize();
+
   // Calculates and returns evictable cache size. In error case, this returns 0.
-  uint64_t CalculateEvictableCacheSize();
+  int64_t CalculateEvictableCacheSize();
 
   // Checks if file corresponding to |id| exists in cache, and returns
   // FILE_ERROR_OK with |cache_file_path| storing the path to the file.
   // |cache_file_path| must not be null.
   FileError GetFile(const std::string& id, base::FilePath* cache_file_path);
 
   // Stores |source_path| as a cache of the remote content of the file
   // with |id| and |md5|.
   // Pass an empty string as MD5 to mark the entry as dirty.
   FileError Store(const std::string& id,
@@ skipping 118 matching lines @@
   // invalidate its weak pointers before any other members are destroyed.
   // This object should be accessed only on |blocking_task_runner_|.
   base::WeakPtrFactory<FileCache> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(FileCache);
 };
 
 }  // namespace internal
 }  // namespace drive
 
 #endif  // COMPONENTS_DRIVE_CHROMEOS_FILE_CACHE_H_