[Telemetry] Migrate browser_test_runner to use typ as the test runner

telemetry/telemetry/testing/serially_executed_browser_test_case.py

Index: telemetry/telemetry/testing/serially_executed_browser_test_case.py
diff --git a/telemetry/telemetry/testing/serially_executed_browser_test_case.py b/telemetry/telemetry/testing/serially_executed_browser_test_case.py
index 3a469cb3cfdd9ee49c86b43efab8d7df81c9f906..7b24e1ae45d9cccb4d730d0e60b78ffa5f8531f3 100644
--- a/telemetry/telemetry/testing/serially_executed_browser_test_case.py
+++ b/telemetry/telemetry/testing/serially_executed_browser_test_case.py
@@ -8,7 +8,7 @@ import unittest
 
 from py_utils import cloud_storage
 from telemetry.internal.browser import browser_finder
-from telemetry.testing import options_for_unittests
+from telemetry.testing import browser_test_context
 from telemetry.util import wpr_modes
 
 
@@ -31,7 +31,7 @@ class SeriallyExecutedBrowserTestCase(unittest.TestCase):
 
   @classmethod
   def setUpClass(cls):
-    cls._finder_options = options_for_unittests.GetCopy()
+    cls._finder_options = browser_test_context.GetCopy().finder_options
     cls.platform = None
     cls.browser = None
     cls._browser_to_create = None
@@ -142,15 +142,24 @@ def LoadAllTestsInModule(module):
     test cases to be run.
   """
   suite = unittest.TestSuite()
-  finder_options = options_for_unittests.GetCopy()
-  if not hasattr(finder_options, 'browser_test_runner_running'):
+  test_context = browser_test_context.GetCopy()
+  if not test_context:
     return suite
   for _, obj in inspect.getmembers(module):
     if (inspect.isclass(obj) and
         issubclass(obj, SeriallyExecutedBrowserTestCase)):
+      # We bail out early if the test class's name doesn't match the targeted
+      # test_class_name in test_context to avoid calling GenerateTestCases for
+      # tests that we don't intend to run. This is to avoid possible errors in
+      # GenerateTestCases as the test class may define custom options in
+      # the finder_options object, and hence would raise error if they can't
+      # find their custom options in finder_options object.
+      if test_context.test_class_name != obj.Name():
+        continue
       for test in GenerateTestCases(
-          test_class=obj, finder_options=finder_options):
-        suite.addTest(test)
+          test_class=obj, finder_options=test_context.finder_options):
+        if test.id() in test_context.test_case_ids_to_run:
+          suite.addTest(test)
   return suite