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

build/android/pylib/local/device/local_device_perf_test_run.py

Index: build/android/pylib/local/device/local_device_perf_test_run.py
diff --git a/build/android/pylib/local/device/local_device_perf_test_run.py b/build/android/pylib/local/device/local_device_perf_test_run.py
index 19e20030e93ebfb40ecb91cb40fc5474134728e0..7e4538d374cc0bbd7fdbddc69f00cc8aab0784cd 100644
--- a/build/android/pylib/local/device/local_device_perf_test_run.py
+++ b/build/android/pylib/local/device/local_device_perf_test_run.py
@@ -206,10 +206,10 @@ class TestShard(object):
     pickled = os.path.join(constants.PERF_OUTPUT_DIR, result['name'])
     if os.path.exists(pickled):
       with file(pickled, 'r') as f:
-        previous = pickle.loads(f.read())
+        previous = pickle.load(f)
         result['output'] = previous['output'] + result['output']
     with file(pickled, 'w') as f:
-      f.write(pickle.dumps(result))
+      pickle.dump(result, f)
 
   def _TestTearDown(self):
     if self._output_dir: