[build/android] Load/dump pickles directly form/to files

build/android/pylib/instrumentation/instrumentation_test_instance.py

 # Copyright 2015 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 collections
 import copy
 import json
 import logging
 import os
 import pickle
@@ skipping 303 matching lines @@
   return tests
 
 
 def _GetTestsFromPickle(pickle_path, jar_path):
   if not os.path.exists(pickle_path):
     raise TestListPickleException('%s does not exist.' % pickle_path)
   if os.path.getmtime(pickle_path) <= os.path.getmtime(jar_path):
     raise TestListPickleException(
         '%s newer than %s.' % (jar_path, pickle_path))
 
-  with open(pickle_path, 'r') as pickle_file:
-    pickle_data = pickle.loads(pickle_file.read())
+  with open(pickle_path, 'r') as f:
+    pickle_data = pickle.load(f)
   jar_md5 = md5sum.CalculateHostMd5Sums(jar_path)[jar_path]
 
   if pickle_data['VERSION'] != _PICKLE_FORMAT_VERSION:
     raise TestListPickleException('PICKLE_FORMAT_VERSION has changed.')
   if pickle_data['JAR_MD5SUM'] != jar_md5:
     raise TestListPickleException('JAR file MD5 sum differs.')
   return pickle_data['TEST_METHODS']
 
 
 def _GetTestsFromProguard(jar_path):
@@ skipping 546 matching lines @@
 
   @staticmethod
   def GenerateTestResults(
       result_code, result_bundle, statuses, start_ms, duration_ms):
     return GenerateTestResults(result_code, result_bundle, statuses,
                                start_ms, duration_ms)
 
   #override
   def TearDown(self):
     pass