drive: Deal with the root directory in the same way as others in MoveOperation.

chrome/browser/google_apis/gdata_wapi_url_generator.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.
 //
 // URL utility functions for Google Documents List API (aka WAPI).
 
 #ifndef CHROME_BROWSER_GOOGLE_APIS_GDATA_WAPI_URL_GENERATOR_H_
 #define CHROME_BROWSER_GOOGLE_APIS_GDATA_WAPI_URL_GENERATOR_H_
 
 #include <string>
@@ skipping 71 matching lines @@
   GURL GenerateResourceEntryUrl(const std::string& resource_id) const;
 
   // Generates a URL for getting the root resource list feed.
   // Used to make changes in the root directory (ex. create a directory in the
   // root directory)
   GURL GenerateResourceListRootUrl() const;
 
   // Generates a URL for getting the account metadata feed.
   GURL GenerateAccountMetadataUrl() const;
 
+  // Generates a URL for getting the root directory's content URL.
+  GURL GenerateRootContentUrl() const;
+
  private:
   const GURL base_url_;
 };
 
 }  // namespace google_apis
 
 #endif  // CHROME_BROWSER_GOOGLE_APIS_GDATA_WAPI_URL_GENERATOR_H_