[Telemetry] Make "discard_first_result" apply to user_stories too.

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 997b904a046d27d18187c681423c492dbffc62c4..278efaba12740061e2c4b37c0b678080d2ea3a34 100644
--- a/tools/perf/benchmarks/session_restore.py
+++ b/tools/perf/benchmarks/session_restore.py
@@ -23,6 +23,7 @@ class _SessionRestoreTypical25(benchmark.Benchmark):
   TODO(slamm): Make SmallProfileCreator and this use the same page_set ref.
   """
   page_set = page_sets.Typical25PageSet
+  tag = None  # override with 'warm' or 'cold'
 
   @classmethod
   def Name(cls):
@@ -48,6 +49,10 @@ class _SessionRestoreTypical25(benchmark.Benchmark):
             small_profile_creator.SmallProfileCreator, profile_type, new_args)
       args.browser_options.profile_dir = profile_dir
 
+  @classmethod
+  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.