Add drive::FileSystem::GetFileByPathForSaving().

chrome/browser/chromeos/drive/file_write_watcher.h

 // Copyright 2013 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_WRITE_WATCHER_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_FILE_WRITE_WATCHER_H_
 
 #include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 28 matching lines @@
   // When modification is detected, it is notified to the |observer| passed to
   // the constructor by calling OnCacheFileUploadNeededByOperation(resource_id).
   //
   // Currently, the modification is watched in "one-shot" manner. That is, once
   // a modification is notified, the watch is deactivated for freeing system
   // resources. As a heuristic to capture the real end of write operations that
   // might be done by several chunked writes, the notification is fired after
   // 5 seconds has passed after the last write operation is detected.
   //
   // TODO(kinaba): investigate the possibility to continuously watch the whole
-  // cache directory.
+  // cache directory. http://crbug.com/269424
   void StartWatch(const base::FilePath& path,
                   const std::string& resource_id,
                   const StartWatchCallback& callback);
 
   // For testing purpose, stops inserting delay between the write detection and
   // notification to the observer.
   void DisableDelayForTesting();
 
  private:
   // Invoked when a modification is observed.
   void OnWriteEvent(const std::string& resource_id);
 
   class FileWriteWatcherImpl;
   scoped_ptr<FileWriteWatcherImpl, util::DestroyHelper> watcher_impl_;
   file_system::OperationObserver* operation_observer_;
 
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<FileWriteWatcher> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(FileWriteWatcher);
 };
 
 }  // namespace internal
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_FILE_WRITE_WATCHER_H_