Revert of [Telemetry] Remove logic of pulling out user_agent_type from page_set

telemetry/telemetry/page/shared_page_state.py

Index: telemetry/telemetry/page/shared_page_state.py
diff --git a/telemetry/telemetry/page/shared_page_state.py b/telemetry/telemetry/page/shared_page_state.py
index 45c6506de500f152187c645a3e3ffb2f070d6f8f..cd76d894462562258d2ae174134783b43a89b781 100644
--- a/telemetry/telemetry/page/shared_page_state.py
+++ b/telemetry/telemetry/page/shared_page_state.py
@@ -58,7 +58,19 @@
       self._test = timeline_based_page_test.TimelineBasedPageTest(test)
     else:
       self._test = test
-    _PrepareFinderOptions(finder_options, self._test, self._device_type)
+    device_type = self._device_type
+    # TODO(aiolos, nednguyen): Remove this logic of pulling out user_agent_type
+    # from story_set once all page_set are converted to story_set
+    # (crbug.com/439512).
+
+    def _IsPageSetInstance(s):
+      # This is needed to avoid importing telemetry.page.page_set which will
+      # cause cyclic import.
+      return 'PageSet' == s.__class__.__name__ or 'PageSet' in (
+          list(c.__name__ for c in s.__class__.__bases__))
+    if not device_type and _IsPageSetInstance(story_set):
+      device_type = story_set.user_agent_type
+    _PrepareFinderOptions(finder_options, self._test, device_type)
     self._browser = None
     self._finder_options = finder_options
     self._possible_browser = self._GetPossibleBrowser(