[Telemetry] Allows concatenating multiple Disabled & Enabled decorators

tools/perf/benchmarks/benchmark_smoke_unittest.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Run the first page of one benchmark for every module.
 
 Only benchmarks that have a composable measurement are included.
 Ideally this test would be comprehensive, however, running one page
 of every benchmark would run impractically long.
 """
@@ skipping 119 matching lines @@
     # Make sure any decorators are propagated from the original declaration.
     # (access to protected members) pylint: disable=W0212
     # TODO(dpranke): Since we only pick the first test from every class
     # (above), if that test is disabled, we'll end up not running *any*
     # test from the class. We should probably discover all of the tests
     # in a class, and then throw the ones we don't need away instead.
 
     # Merge decorators.
     for attribute in ['_enabled_strings', '_disabled_strings']:
       # Do set union of attributes to eliminate duplicates.
-      merged_attributes = list(set(getattr(method, attribute, []) +
-                                   getattr(benchmark, attribute, [])))
+      merged_attributes = getattr(method, attribute, set()).union(
+          getattr(benchmark, attribute, set()))
       if merged_attributes:
         setattr(method, attribute, merged_attributes)
 
       # Handle the case where the benchmark is Enabled/Disabled everywhere.
-      if (getattr(method, attribute, None) == [] or
-          getattr(benchmark, attribute, None) == []):
-        setattr(method, attribute, [])
+      if (getattr(method, attribute, None) or

[aiolos (Not reviewing), 2015/11/06 18:37:39]

Shouldn't this be 

if (not getattr(...) or
    not getattr(...)):

[nednguyen, 2015/11/06 18:47:24]

Done. Good catch

+          getattr(benchmark, attribute, None)):
+        setattr(method, attribute, set())
 
     # Disable some tests on android platform only.
     if sys.modules[benchmark.__module__] in _ANDROID_BLACK_LIST_MODULES:
-      method._disabled_strings.append('android')
+      method._disabled_strings.add('android')
 
     # TODO(bashi): Remove once crrev.com/1266833004 is landed.
     if benchmark.Name() == 'memory.blink_memory_mobile':
-      method._disabled_strings.append('android')
+      method._disabled_strings.add('android')
 
     setattr(BenchmarkSmokeTest, benchmark.Name(), method)
 
     suite.addTest(BenchmarkSmokeTest(benchmark.Name()))
 
   return suite