[Android] Fix new pylint errors in build/android/.

build/android/pylib/perf/surface_stats_collector.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.
 
 import Queue
 import datetime
 import logging
 import re
 import threading
 from pylib import android_commands
 from pylib.device import device_utils
 
 
 # Log marker containing SurfaceTexture timestamps.
 _SURFACE_TEXTURE_TIMESTAMPS_MESSAGE = 'SurfaceTexture update timestamps'
-_SURFACE_TEXTURE_TIMESTAMP_RE = '\d+'
+_SURFACE_TEXTURE_TIMESTAMP_RE = r'\d+'
 
 _MIN_NORMALIZED_FRAME_LENGTH = 0.5
 
 
 class SurfaceStatsCollector(object):
   """Collects surface stats for a SurfaceView from the output of SurfaceFlinger.
 
   Args:
     device: A DeviceUtils instance.
   """
@@ skipping 56 matching lines @@
         SurfaceStatsCollector.Result('jank_count', None, 'janks'),
         SurfaceStatsCollector.Result('max_frame_delay', None, 'vsyncs'),
         SurfaceStatsCollector.Result('frame_lengths', None, 'vsyncs'),
         SurfaceStatsCollector.Result('avg_surface_fps', None, 'fps')
     ]
 
   @staticmethod
   def _GetNormalizedDeltas(data, refresh_period, min_normalized_delta=None):
     deltas = [t2 - t1 for t1, t2 in zip(data, data[1:])]
     if min_normalized_delta != None:
-      deltas = filter(lambda d: d / refresh_period >= min_normalized_delta,
-                      deltas)
+      deltas = [d for d in deltas
+                if d / refresh_period >= min_normalized_delta]
     return (deltas, [delta / refresh_period for delta in deltas])
 
   @staticmethod
   def _CalculateResults(refresh_period, timestamps, result_suffix):
     """Returns a list of SurfaceStatsCollector.Result."""
     frame_count = len(timestamps)
     seconds = timestamps[-1] - timestamps[0]
 
     frame_lengths, normalized_frame_lengths = \
         SurfaceStatsCollector._GetNormalizedDeltas(
@@ skipping 185 matching lines @@
        and timestamp.
 
     Calculate FPS by measuring the difference of Surface index returned by
     SurfaceFlinger in a period of time.
 
     Returns:
       Dict of {page_flip_count (or 0 if there was an error), timestamp}.
     """
     results = self._device.RunShellCommand('service call SurfaceFlinger 1013')
     assert len(results) == 1
-    match = re.search('^Result: Parcel\((\w+)', results[0])
+    match = re.search(r'^Result: Parcel\((\w+)', results[0])
     cur_surface = 0
     if match:
       try:
         cur_surface = int(match.group(1), 16)
       except Exception:
         logging.error('Failed to parse current surface from ' + match.group(1))
     else:
       logging.warning('Failed to call SurfaceFlinger surface ' + results[0])
     return {
         'page_flip_count': cur_surface,
         'timestamp': datetime.datetime.now(),
     }