Fix baselineoptimizer issue when deleting a virtual baseline not controlled by scm

Tools/Scripts/webkitpy/common/checkout/baselineoptimizer.py

 # Copyright (C) 2011, Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 296 matching lines @@
         for port_name in self._port_names:
             directories = self._relative_baseline_search_paths(port_name, non_virtual_baseline_name)
             for directory in directories:
                 if directory not in results_by_directory:
                     continue
                 if results_by_directory[directory] != root_sha1:
                     return
                 break
 
         _log.debug("Deleting redundant virtual root expected result.")
-        if self._skip_scm_commands:
-            self._files_to_delete.append(virtual_root_expected_baseline_path)
+        if self._scm.exists(virtual_root_expected_baseline_path):
+            _log.debug("    Deleting (SCM): " + virtual_root_expected_baseline_path)
+            if self._skip_scm_commands:
+                self._files_to_delete.append(virtual_root_expected_baseline_path)
+            else:
+                self._scm.delete(virtual_root_expected_baseline_path)
         else:
-            self._scm.delete(virtual_root_expected_baseline_path)
+            _log.debug("    Deleting (file system): " + virtual_root_expected_baseline_path)
+            self._filesystem.remove(virtual_root_expected_baseline_path)
 
     def optimize(self, baseline_name):
         # The virtual fallback path is the same as the non-virtual one tacked on to the bottom of the non-virtual path.
         # See https://docs.google.com/a/chromium.org/drawings/d/1eGdsIKzJ2dxDDBbUaIABrN4aMLD1bqJTfyxNGZsTdmg/edit for
         # a visual representation of this.
         #
         # So, we can optimize the virtual path, then the virtual root and then the regular path.
 
         _log.debug("Optimizing regular fallback path.")
         result = self._optimize_subtree(baseline_name)
         non_virtual_baseline_name = self._port_factory.get().lookup_virtual_test_base(baseline_name)
         if not non_virtual_baseline_name:
             return result, self._files_to_delete, self._files_to_add
 
         self._optimize_virtual_root(baseline_name, non_virtual_baseline_name)
 
         _log.debug("Optimizing non-virtual fallback path.")
         result |= self._optimize_subtree(non_virtual_baseline_name)
         return result, self._files_to_delete, self._files_to_add