Sync FileSystem: Use app id part of the URL for its directory title.

chrome/browser/sync_file_system/drive_file_sync_client.h

Index: chrome/browser/sync_file_system/drive_file_sync_client.h
diff --git a/chrome/browser/sync_file_system/drive_file_sync_client.h b/chrome/browser/sync_file_system/drive_file_sync_client.h
index 48043d69bcc80bfe75adc49ee2ef2236e87d00c3..368209a8326b8b259061fde690bcb7c4c585290f 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_client.h
+++ b/chrome/browser/sync_file_system/drive_file_sync_client.h
@@ -150,6 +150,9 @@ class DriveFileSyncClient : public base::NonThreadSafe,
                   const std::string& remote_file_md5,
                   const GDataErrorCallback& callback);
 
+  static std::string OriginToDirectoryTitle(const GURL& origin);
+  static GURL DirectoryTitleToOrigin(const std::string& title);
+
  private:
   friend class DriveFileSyncClientTest;
   friend class DriveFileSyncServiceTest;