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

chrome/browser/google_apis/gdata_wapi_url_generator.h

Index: chrome/browser/google_apis/gdata_wapi_url_generator.h
diff --git a/chrome/browser/google_apis/gdata_wapi_url_generator.h b/chrome/browser/google_apis/gdata_wapi_url_generator.h
index 5700ba7cf94d875884e33c90594531006d0a7140..07171889b0825d93e14a9ba77ff0ed4140f47956 100644
--- a/chrome/browser/google_apis/gdata_wapi_url_generator.h
+++ b/chrome/browser/google_apis/gdata_wapi_url_generator.h
@@ -89,6 +89,9 @@ class GDataWapiUrlGenerator {
   // 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_;
 };