Move user_story.user_story_set to story.story_set

tools/perf/benchmarks/session_restore.py

Index: tools/perf/benchmarks/session_restore.py
diff --git a/tools/perf/benchmarks/session_restore.py b/tools/perf/benchmarks/session_restore.py
index 86509f35d387326f3cff964f10e27e6418123a35..3aa2e089a431f143f2d106cdc9f4dafddcbc99e5 100644
--- a/tools/perf/benchmarks/session_restore.py
+++ b/tools/perf/benchmarks/session_restore.py
@@ -55,17 +55,17 @@ class _SessionRestoreTypical25(benchmark.Benchmark):
   def ValueCanBeAddedPredicate(cls, _, is_first_result):
     return cls.tag == 'cold' or not is_first_result
 
-  def CreateUserStorySet(self, _):
-    """Return a user story set that only has the first user story.
+  def CreateStorySet(self, _):
+    """Return a story set that only has the first user story.
 
     The session restore measurement skips the navigation step and
     only tests session restore by having the browser start-up.
     The first user story is used to get WPR set up and hold results.
     """
-    user_story_set = self.page_set()
-    for user_story in user_story_set.user_stories[1:]:
-      user_story_set.RemoveUserStory(user_story)
-    return user_story_set
+    story_set = self.page_set()
+    for user_story in story_set.user_stories[1:]:
+      story_set.RemoveUserStory(user_story)
+    return story_set
 
   def CreatePageTest(self, options):
     is_cold = (self.tag == 'cold')