Reland of Migrate DeviceUtils.ReadFile to adb_wrapper (try 3)

tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper_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.
 
 import os
 import pickle
 import re
 import shutil
 import tempfile
 import unittest
 
 from telemetry import decorators
 from telemetry.core import util
 from telemetry.core.platform.profiler import android_profiling_helper
 from telemetry.unittest_util import simple_mock
 from telemetry.unittest_util import tab_test_case
 
 
 def _GetLibrariesMappedIntoProcesses(device, pids):
   libs = set()
   for pid in pids:
     maps_file = '/proc/%d/maps' % pid
-    maps = device.ReadFile(maps_file, as_root=True)
+    maps = device.ReadFile(maps_file, as_root=True).splitlines()
     for map_line in maps:
       lib = re.match(r'.*\s(/.*[.]so)$', map_line)
       if lib:
         libs.add(lib.group(1))
   return libs
 
 
 class TestAndroidProfilingHelper(unittest.TestCase):
 
   def testGetRequiredLibrariesForPerfProfile(self):
@@ skipping 97 matching lines @@
 
   # Test fails: crbug.com/437081
   # @decorators.Enabled('android')
   @decorators.Disabled
   def testGetToolchainBinaryPath(self):
     with tempfile.NamedTemporaryFile() as libc:
       self._device.PullFile('/system/lib/libc.so', libc.name)
       path = android_profiling_helper.GetToolchainBinaryPath(libc.name,
                                                              'objdump')
       assert os.path.exists(path)