drive: Change FileCache::GetCacheEntry's return type to FileError

chrome/browser/chromeos/drive/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 CHROME_BROWSER_CHROMEOS_DRIVE_FILE_CACHE_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_FILE_CACHE_H_
 
 #include <set>
 #include <string>
 
@@ skipping 52 matching lines @@
             FreeDiskSpaceGetterInterface* free_disk_space_getter);
 
   // Returns true if the given path is under drive cache directory, i.e.
   // <user_profile_dir>/GCache/v1
   //
   // Can be called on any thread.
   bool IsUnderFileCacheDirectory(const base::FilePath& path) const;
 
   // Gets the cache entry for file corresponding to |id| and returns true if
   // entry exists in cache map.
-  bool GetCacheEntry(const std::string& id, FileCacheEntry* entry);
+  FileError GetCacheEntry(const std::string& id, FileCacheEntry* entry);
 
   // Returns an object to iterate over entries.
   scoped_ptr<Iterator> GetIterator();
 
   // Frees up disk space to store a file with |num_bytes| size content, while
   // keeping cryptohome::kMinFreeSpaceInBytes bytes on the disk, if needed.
   // Returns true if we successfully manage to have enough space, otherwise
   // false.
   bool FreeDiskSpaceIfNeededFor(int64 num_bytes);
 
@@ skipping 108 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  // CHROME_BROWSER_CHROMEOS_DRIVE_FILE_CACHE_H_