Split file_observers.h into three files for each class

webkit/browser/fileapi/file_access_observer.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 WEBKIT_BROWSER_FILEAPI_FILE_ACCESS_OBSERVER_H_
+#define WEBKIT_BROWSER_FILEAPI_FILE_ACCESS_OBSERVER_H_
+
+namespace fileapi {
+
+class FileSystemURL;
+
+// An abstract interface to observe file access.
+// OnAccess is called whenever an operation reads file contents or metadata.
+// (It is called only once per operation regardless of whether the operation
+// is recursive or not)
+class FileAccessObserver {
+ public:
+  FileAccessObserver() {}
+  virtual ~FileAccessObserver() {}
+
+  virtual void OnAccess(const FileSystemURL& url) = 0;

[jam, 2013/10/08 16:07:29]

btw we prefer callbacks instead of one method interfaces

+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FileAccessObserver);
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_BROWSER_FILEAPI_FILE_ACCESS_OBSERVER_H_