Re-enable last remaining key_silk_cases tests on Android

tools/perf/benchmarks/thread_times.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.
 from telemetry import test
 
 from benchmarks import silk_flags
 from measurements import thread_times
 
 
-@test.Disabled('android')  # crbug.com/355952
 class ThreadTimesKeySilkCases(test.Test):
   """Measures timeline metrics while performing smoothness action on key silk
   cases."""
   test = thread_times.ThreadTimes
   page_set = 'page_sets/key_silk_cases.py'
   options = {"report_silk_results": True}
 
 
-@test.Disabled('android')  # crbug.com/355952
 class ThreadTimesFastPathKeySilkCases(test.Test):
   """Measures timeline metrics while performing smoothness action on key silk
   cases using bleeding edge rendering fast paths."""
   tag = 'fast_path'
   test = thread_times.ThreadTimes
   page_set = 'page_sets/key_silk_cases.py'
   options = {"report_silk_results": True}
   def CustomizeBrowserOptions(self, options):
     silk_flags.CustomizeBrowserOptionsForFastPath(options)
 
@@ skipping 22 matching lines @@
   page_set = 'page_sets/tough_compositor_cases.py'
 
 
 @test.Enabled('android')
 class ThreadTimesPolymer(test.Test):
   """Measures timeline metrics while performing smoothness action on
   Polymer cases."""
   test = thread_times.ThreadTimes
   page_set = "page_sets/polymer.py"
   options = { 'report_silk_results': True }