[test] Refactoring - Use subject/observer pattern for progress indicators.

tools/run-tests.py

 #!/usr/bin/env python
 #
 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 596 matching lines @@
       test_id += 1
 
   if options.cat:
     return 0  # We're done here.
 
   if options.report:
     verbose.PrintReport(all_tests)
 
   # Run the tests, either locally or distributed on the network.
   start_time = time.time()
-  progress_indicator = progress.PROGRESS_INDICATORS[options.progress]()
+  progress_indicator = progress.IndicatorNotifier()
+  progress_indicator.register(progress.PROGRESS_INDICATORS[options.progress]())
   if options.junitout:
-    progress_indicator = progress.JUnitTestProgressIndicator(
-        progress_indicator, options.junitout, options.junittestsuite)
+    progress_indicator.register(progress.JUnitTestProgressIndicator(
+        options.junitout, options.junittestsuite))
   if options.json_test_results:
-    progress_indicator = progress.JsonTestProgressIndicator(
-        progress_indicator, options.json_test_results, arch,
-        MODES[mode]["execution_mode"])
+    progress_indicator.register(progress.JsonTestProgressIndicator(
+        options.json_test_results, arch, MODES[mode]["execution_mode"]))
 
   run_networked = not options.no_network
   if not run_networked:
     print("Network distribution disabled, running tests locally.")
   elif utils.GuessOS() != "linux":
     print("Network distribution is only supported on Linux, sorry!")
     run_networked = False
   peers = []
   if run_networked:
     peers = network_execution.GetPeers()
@@ skipping 16 matching lines @@
   exit_code = runner.Run(options.j)
   overall_duration = time.time() - start_time
 
   if options.time:
     verbose.PrintTestDurations(suites, overall_duration)
   return exit_code
 
 
 if __name__ == "__main__":
   sys.exit(Main())