[Android] Switch to DeviceUtils versions of file functions.

tools/memory_inspector/memory_inspector/backends/android/android_backend_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.
 
 """Unittests for the backends.android modules."""
 
 import os
 import unittest
 
 from memory_inspector.backends import prebuilts_fetcher
@@ skipping 21 matching lines @@
     """shared_other_unevictable=0 shared_other=0 "" [AA==]
 400f4000-400f5000 r--p 0 private_unevictable=4096 private=4096 shared_app=[] """
     """shared_other_unevictable=0 shared_other=0 "" [AQ==]
 40127000-40147000 rw-s 0 private_unevictable=4096 private=4096 shared_app=[] """
     """shared_other_unevictable=32768 shared_other=32768 "/X" [/////w==]
 be8b7000-be8d8000 rw-p 0 private_unevictable=8192 private=8192 shared_app=[] """
     """shared_other_unevictable=4096 shared_other=12288 "[stack]" [AAAA4AE=]
 ffff0000-ffff1000 r-xp 0 private_unevictable=0 private=0 shared_app=[] """
     """shared_other_unevictable=0 shared_other=0 "[vectors]" [AA==]""")
 
-_MOCH_DUMPHEAP_OUT = """Android Native Heap Dump v1.0
+_MOCK_DUMPHEAP_OUT = """Android Native Heap Dump v1.0
 
 Total memory: 1608601
 Allocation records: 2
 
 z 1  sz    100    num    2  bt 9dcd1000 9dcd2000 b570e100 b570e000
 z 0  sz    1000   num    3  bt b570e100 00001234 b570e200
 MAPS
 9dcd0000-9dcd6000 r-xp 00000000 103:00 815       /system/lib/libnbaio.so
 9dcd6000-9dcd7000 r--p 00005000 103:00 815       /system/lib/libnbaio.so
 9dcd7000-9dcd8000 rw-p 00006000 103:00 815       /system/lib/libnbaio.so
@@ skipping 25 matching lines @@
   def setUp(self):
     prebuilts_fetcher.in_test_harness = True
     self._mock_adb = mock_adb.MockAdb()
     planned_adb_responses = {
       'devices': _MOCK_DEVICES_OUT,
       'shell getprop ro.product.model': 'Mock device',
       'shell getprop ro.build.type': 'userdebug',
       'root': 'adbd is already running as root',
       'shell /data/local/tmp/ps_ext': _MOCK_PS_EXT_OUT,
       'shell /data/local/tmp/memdump': _MOCK_MEMDUMP_OUT,
-      'shell cat "/data/local/tmp/heap': _MOCH_DUMPHEAP_OUT,
+      'shell cat "/data/local/tmp/heap': _MOCK_DUMPHEAP_OUT,
+      'shell test -e "/data/local/tmp/heap': '0',
     }
     for (cmd, response) in planned_adb_responses.iteritems():
       self._mock_adb.PrepareResponse(cmd, response)
     self._mock_adb.Start()
 
   def runTest(self):
     ab = android_backend.AndroidBackend()
 
     # Test settings load/store logic and setup the mock adb path.
     self.assertTrue('adb_path' in ab.settings.expected_keys)
@@ skipping 78 matching lines @@
     self.assertEqual(alloc_2.total_size, 3000)
     self.assertEqual(alloc_2.stack_trace.depth, 3)
     # 0x00001234 is not present in the maps. It should be parsed anyways but
     # no executable info is expected.
     self.assertEqual(alloc_2.stack_trace[1].address, 0x00001234)
     self.assertIsNone(alloc_2.stack_trace[1].exec_file_rel_path)
     self.assertIsNone(alloc_2.stack_trace[1].offset)
 
   def tearDown(self):
     self._mock_adb.Stop()