Android GTest Runner: Handle test filters that start / end with :

build/android/pylib/local/device/local_device_gtest_run.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.
 
 import imp
 import itertools
 import os
 import posixpath
 
 from devil.android import device_errors
@@ skipping 73 matching lines @@
   # wildcard comes at the end and there is at least one . to prove the scope is
   # not too large.
   # This heuristic is not necessarily faster, but normally is.
   if len(patterns) == 1 and patterns[0].endswith('*'):
     no_suffix = patterns[0].rstrip('*')
     if '*' not in no_suffix and '.' in no_suffix:
       return patterns
 
   if '*' in gtest_filter:
     return None
-  return patterns
+  return [p for p in patterns if p]  # Ignore empty entries.
 
 
 class _ApkDelegate(object):
   def __init__(self, test_instance):
     self._activity = test_instance.activity
     self._apk_helper = test_instance.apk_helper
     self._package = test_instance.package
     self._runner = test_instance.runner
     self._permissions = test_instance.permissions
     self._suite = test_instance.suite
@@ skipping 249 matching lines @@
   def TearDown(self):
     @local_device_test_run.handle_shard_failures
     def individual_device_tear_down(dev):
       for s in self._servers.get(str(dev), []):
         s.TearDown()
 
       tool = self.GetTool(dev)
       tool.CleanUpEnvironment()
 
     self._env.parallel_devices.pMap(individual_device_tear_down)