Update from https://crrev.com/303153

build/android/pylib/utils/device_temp_file.py

+# Copyright 2013 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.
+
+"""A temp file that automatically gets pushed and deleted from a device."""
+
+# pylint: disable=W0622
+
+import random
+import time
+
+class DeviceTempFile(object):
+  def __init__(self, device, prefix='temp_file', suffix=''):
+    """Find an unused temporary file path in the devices external directory.
+
+    When this object is closed, the file will be deleted on the device.
+
+    Args:
+      device: An instance of DeviceUtils
+      prefix: The prefix of the name of the temp file.
+      suffix: The suffix of the name of the temp file.
+    """
+    self._device = device
+    while True:
+      i = random.randint(0, 1000000)
+      self.name = '%s/%s-%d-%010d%s' % (
+          self._device.GetExternalStoragePath(),
+          prefix, int(time.time()), i, suffix)
+      if not self._device.FileExists(self.name):
+        break
+    # Immediately create an empty file so that other temp files can't
+    # be given the same name.
+    # |as_root| must be set to False due to the implementation of |WriteFile|.
+    # Having |as_root| be True may cause infinite recursion.
+    self._device.WriteFile(self.name, '', as_root=False)
+
+  def close(self):
+    """Deletes the temporary file from the device."""
+    self._device.RunShellCommand(['rm', self.name])
+
+  def __enter__(self):
+    return self
+
+  def __exit__(self, type, value, traceback):
+    self.close()