drive: Rewrite UpdateOpreation to access cache/metadata on the blocking pool

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 <string>
 #include <vector>
 
@@ skipping 244 matching lines @@
                            const FileOperationCallback& callback);
 
   // Modifies cache state, i.e. creates symlink in outgoing
   // dir to reference dirty file in persistent dir.
   // |callback| must not be null.
   // Must be called on the UI thread.
   void CommitDirtyOnUIThread(const std::string& resource_id,
                              const std::string& md5,
                              const FileOperationCallback& callback);
 
-  // Modifies cache state, which involves the following:
-  // - moves |source_path| to |dest_path| in persistent dir if
-  //   file is pinned or tmp dir otherwise, where |source_path| has .local
-  //   extension and |dest_path| has .<md5> extension
-  // - deletes symlink in outgoing dir
-  // - if file is pinned, updates symlink in pinned dir to reference
-  //   |dest_path|
-  // |callback| must not be null.
-  // Must be called on the UI thread.
-  void ClearDirtyOnUIThread(const std::string& resource_id,
-                            const std::string& md5,
-                            const FileOperationCallback& callback);
+  // Clears dirty state of the specified entry.
+  FileError ClearDirty(const std::string& resource_id,
+                       const std::string& md5);
 
   // Runs Remove() on |blocking_task_runner_| and runs |callback| with the
   // result.
   // Must be called on the UI thread.
   void RemoveOnUIThread(const std::string& resource_id,
                         const FileOperationCallback& callback);
 
   // Removes the specified cache entry and delete cache files if available.
   // Synchronous version of RemoveOnUIThread().
   FileError Remove(const std::string& resource_id);
@@ skipping 87 matching lines @@
                           const std::string& md5,
                           base::FilePath* cache_file_path);
 
   // Used to implement MarkAsUnmountedOnUIThread.
   FileError MarkAsUnmounted(const base::FilePath& file_path);
 
   // Used to implement MarkDirtyOnUIThread.
   FileError MarkDirty(const std::string& resource_id,
                       const std::string& md5);
 
-  // Used to implement ClearDirtyOnUIThread.
-  FileError ClearDirty(const std::string& resource_id,
-                       const std::string& md5);
-
   // Used to implement ClearAllOnUIThread.
   bool ClearAll();
 
   // Runs callback and notifies the observers when file is pinned.
   void OnPinned(const std::string& resource_id,
                 const std::string& md5,
                 const FileOperationCallback& callback,
                 FileError error);
 
   // Runs callback and notifies the observers when file is unpinned.
@@ skipping 37 matching lines @@
 // this value.
 //
 // Copied from cryptohome/homedirs.h.
 // TODO(satorux): Share the constant.
 const int64 kMinFreeSpace = 512 * 1LL << 20;
 
 }  // namespace internal
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_FILE_CACHE_H_