Creating named directory for bisect test runs.

scripts/slave/recipe_modules/auto_bisect_staging/api.py

Index: scripts/slave/recipe_modules/auto_bisect_staging/api.py
diff --git a/scripts/slave/recipe_modules/auto_bisect_staging/api.py b/scripts/slave/recipe_modules/auto_bisect_staging/api.py
index a519eac10144ad0a9fb1b84a1466cd07a9f4889f..31d0529efe5f6c8989ba80e584c3428720d41aa4 100644
--- a/scripts/slave/recipe_modules/auto_bisect_staging/api.py
+++ b/scripts/slave/recipe_modules/auto_bisect_staging/api.py
@@ -174,6 +174,10 @@ class AutoBisectStagingApi(recipe_api.RecipeApi):
 
     This is for the merged director/tester flow.
     """
+    with self.m.step.nest('Clearing results directory'):
+      results_dir = self.m.path['bisect_results']
+      self.m.file.rmtree('old results directory', results_dir)
+      self.m.file.makedirs('new results directory', results_dir)
     if self.m.platform.is_win:
       self.m.chromium.taskkill()