Revert of Refactor serving_dirs.

tools/telemetry/telemetry/user_story/user_story_runner.py

Index: tools/telemetry/telemetry/user_story/user_story_runner.py
diff --git a/tools/telemetry/telemetry/user_story/user_story_runner.py b/tools/telemetry/telemetry/user_story/user_story_runner.py
index 0ec2b548bc352c57d72eb3dea35dd5e20ef52cb0..4eb547b7c7be2e81c134f4520fe4b6fc360a42f8 100644
--- a/tools/telemetry/telemetry/user_story/user_story_runner.py
+++ b/tools/telemetry/telemetry/user_story/user_story_runner.py
@@ -9,6 +9,7 @@
 import sys
 import time
 
+from telemetry import decorators
 from telemetry import page as page_module
 from telemetry.core import exceptions
 from telemetry.core import wpr_modes
@@ -19,6 +20,7 @@
 from telemetry.user_story import user_story_filter
 from telemetry.user_story import user_story_set as user_story_set_module
 from telemetry.util import cloud_storage
+from telemetry.util import exception_formatter
 from telemetry.value import failure
 from telemetry.value import skip
 
@@ -114,6 +116,28 @@
       exception_formatter.PrintFormattedException(
           msg='Exception from DidRunUserStory: ')
 
+@decorators.Cache
+def _UpdateUserStoryArchivesIfChanged(user_story_set):
+  # Scan every serving directory for .sha1 files
+  # and download them from Cloud Storage. Assume all data is public.
+  all_serving_dirs = user_story_set.serving_dirs.copy()
+  # Add individual page dirs to all serving dirs.
+  for user_story in user_story_set:
+    if isinstance(user_story, page_module.Page) and user_story.is_file:
+      all_serving_dirs.add(user_story.serving_dir)
+  # Scan all serving dirs.
+  for serving_dir in all_serving_dirs:
+    if os.path.splitdrive(serving_dir)[1] == '/':
+      raise ValueError('Trying to serve root directory from HTTP server.')
+    for dirpath, _, filenames in os.walk(serving_dir):
+      for filename in filenames:
+        path, extension = os.path.splitext(
+            os.path.join(dirpath, filename))
+        if extension != '.sha1':
+          continue
+        cloud_storage.GetIfChanged(path, user_story_set.bucket)
+
+
 class UserStoryGroup(object):
   def __init__(self, shared_user_story_state_class):
     self._shared_user_story_state_class = shared_user_story_state_class
@@ -183,10 +207,7 @@
 
   if (not finder_options.use_live_sites and user_story_set.bucket and
       finder_options.browser_options.wpr_mode != wpr_modes.WPR_RECORD):
-    serving_dirs = user_story_set.serving_dirs
-    for directory in serving_dirs:
-      cloud_storage.GetFilesInDirectoryIfChanged(directory,
-                                                 user_story_set.bucket)
+    _UpdateUserStoryArchivesIfChanged(user_story_set)
     if not _UpdateAndCheckArchives(
         user_story_set.archive_data_file, user_story_set.wpr_archive_info,
         user_stories):