Disable failing perf unit tests on chromeos.

tools/perf/measurements/thread_times_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.
 
 from telemetry.core import wpr_modes
 from telemetry import decorators
 from telemetry.page import page
 from telemetry.unittest_util import options_for_unittests
 from telemetry.unittest_util import page_test_test_case
 
@@ skipping 36 matching lines @@
     measurement = thread_times.ThreadTimes()
     timeline_options = self._options
     results = self.RunMeasurement(measurement, ps, options = timeline_options)
     self.assertEquals(0, len(results.failures))
 
     for category in timeline.TimelineThreadCategories.values():
       cpu_time_name = timeline.ThreadCpuTimeResultName(category)
       cpu_time = results.FindAllPageSpecificValuesNamed(cpu_time_name)
       self.assertEquals(len(cpu_time), 1)
 
+  @decorators.Disabled('chromeos')  # crbug.com/483212
   def testWithSilkDetails(self):
     ps = self.CreatePageSetFromFileInUnittestDataDir('scrollable_page.html')
     measurement = thread_times.ThreadTimes(report_silk_details=True)
     results = self.RunMeasurement(measurement, ps, options = self._options)
     self.assertEquals(0, len(results.failures))
 
     main_thread = "renderer_main"
     expected_trace_categories = ["blink", "cc", "idle"]
     for trace_category in expected_trace_categories:
       value_name = timeline.ThreadDetailResultName(main_thread, trace_category)
       values = results.FindAllPageSpecificValuesNamed(value_name)
       self.assertEquals(len(values), 1)
 
   def testCleanUpTrace(self):
     self.TestTracingCleanedUp(thread_times.ThreadTimes, self._options)