Rename the drive: scheme with the externalfile: scheme.

chrome/browser/chromeos/fileapi/external_file_url_util.h

+// Copyright 2014 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_FILEAPI_EXTERNAL_FILE_URL_UTIL_H_
+#define CHROME_BROWSER_CHROMEOS_FILEAPI_EXTERNAL_FILE_URL_UTIL_H_
+
+class GURL;
+class Profile;
+
+namespace base {
+class FilePath;
+}
+
+namespace chromeos {
+
+// Returns the external file resource url formatted as "externalfile:<path>"
+GURL FilePathToExternalFileURL(const base::FilePath& path);
+
+// Converts a externalfile: URL back to a path that can be passed to FileSystem.
+base::FilePath ExternalFileURLToFilePath(const GURL& url);
+
+// Overwrites |url| with an external file URL when appropriate.

[mtomasz, 2014/09/22 01:58:48]

When is it appropriate? Could you please describe when the url will be replaced?
Also, how about simplifying the interface?

GURL CreateExternalFileURL(Profile* profile, const base::FilePath);

[hirono, 2014/09/22 03:32:19]

I updated the function signature and comments. Thank you!

+void MaybeSetExternalFileURL(Profile* profile,
+                             const base::FilePath& path,
+                             GURL* url);
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_FILEAPI_EXTERNAL_FILE_URL_UTIL_H_