Don't duplicate virtual and non-virtual baselines.

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

 # Copyright (C) 2011, Google Inc. All rights reserved.
 #
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 # modification, are permitted provided that the following conditions are
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 #
 #     * Redistributions of source code must retain the above copyright
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@@ skipping 63 matching lines @@
             return port.virtual_baseline_search_path(baseline_name)
         return port.baseline_search_path()
 
     def _virtual_suite(self, baseline_name):
         return self._default_port.lookup_virtual_suite(baseline_name)
 
     def _virtual_base(self, baseline_name):
         return self._default_port.lookup_virtual_test_base(baseline_name)
 
     def _relative_baseline_search_paths(self, port, baseline_name):
-        baseline_search_path = self._baseline_search_path(port, baseline_name)
-        baseline_root = self._baseline_root(baseline_name)
-        relative_paths = [self._filesystem.relpath(path, self._webkit_base) for path in baseline_search_path]
-        return relative_paths + [baseline_root]
+        directories = self._baseline_search_path(port, baseline_name)
+        directories = [self._filesystem.relpath(path, self._webkit_base) for path in directories]
+        directories.append(self._baseline_root(baseline_name))

[Dirk Pranke, 2016/12/18 04:26:00]

Stylistically, I don't tend to like repeatedly modifying variables
in place like this. I'd probably write this as something more like:

directories = ([self._filesystem.replath(path, self._webkit_base)
                for path in self._baseline_search_path(port, baseline_name)] + 
               [self._baseline_root(baseline_name)])

+
+        virtual_suite = self._virtual_suite(baseline_name)
+        if virtual_suite:
+            non_virtual_directories = port.baseline_search_path()
+            non_virtual_directories = [self._filesystem.relpath(path, self._webkit_base) for path in non_virtual_directories]
+            non_virtual_directories.append(self.ROOT_LAYOUT_TESTS_DIRECTORY)
+            non_virtual_directories = [self._filesystem.join(path, virtual_suite.base) for path in non_virtual_directories]
+            directories += non_virtual_directories

[Dirk Pranke, 2016/12/18 04:26:00]

and similar.

+
+        return directories
 
     def _join_directory(self, directory, baseline_name):
         # This code is complicated because both the directory name and the baseline_name have the virtual
         # test suite in the name and the virtual baseline name is not a strict superset of the non-virtual name.
         # For example, virtual/gpu/fast/canvas/foo-expected.png corresponds to fast/canvas/foo-expected.png and
         # the baseline directories are like platform/mac/virtual/gpu/fast/canvas. So, to get the path
         # to the baseline in the platform directory, we need to append just foo-expected.png to the directory.
         virtual_suite = self._virtual_suite(baseline_name)
         if virtual_suite:
             baseline_name_without_virtual = baseline_name[len(virtual_suite.name) + 1:]
@@ skipping 222 matching lines @@
         result = self._optimize_subtree(baseline_name)
         non_virtual_baseline_name = self._virtual_base(baseline_name)
         if not non_virtual_baseline_name:
             return result
 
         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