Revert 164876 - Set root resource ID upon full feed update.

chrome/browser/chromeos/drive/drive_feed_loader.h

Index: chrome/browser/chromeos/drive/drive_feed_loader.h
===================================================================
--- chrome/browser/chromeos/drive/drive_feed_loader.h	(revision 164882)
+++ chrome/browser/chromeos/drive/drive_feed_loader.h	(working copy)
@@ -76,9 +76,6 @@
   FileOperationCallback load_finished_callback;
   ScopedVector<google_apis::DocumentFeed> feed_list;
   scoped_ptr<GetDocumentsUiState> ui_state;
-  // On initial feed load for Drive API, remember root ID for
-  // DriveResourceData initialization later in UpdateFromFeed().
-  std::string root_resource_id;
 };
 
 // Defines set of parameters sent to callback OnProtoLoaded().
@@ -141,12 +138,10 @@
   //
   // See comments at DriveFeedProcessor::ApplyFeeds() for
   // |start_changestamp| and |root_feed_changestamp|.
-  // |root_resource_id| is used for Drive API.
   void UpdateFromFeed(
-      const ScopedVector<google_apis::DocumentFeed>& feed_list,
-      int64 start_changestamp,
-      int64 root_feed_changestamp,
-      const std::string& root_resource_id);
+    const ScopedVector<google_apis::DocumentFeed>& feed_list,
+    int64 start_changestamp,
+    int64 root_feed_changestamp);
 
   // Indicates whether there is a feed refreshing server request is in flight.
   bool refreshing() const { return refreshing_; }