Fix style in tools/auto_bisect.

tools/auto_bisect/bisect_utils.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.
 
 """Utility functions used by the bisect tool.
 
 This includes functions related to checking out the depot and outputting
 annotations for the Buildbot waterfall.
 """
 
@@ skipping 300 matching lines @@
   spec = ''.join([l for l in spec.splitlines()])
 
   if 'android' in opts.target_platform:
     spec += GCLIENT_SPEC_ANDROID
 
   return_code = RunGClient(
       ['config', '--spec=%s' % spec], cwd=cwd)
   return return_code
 
 
-
 def OnAccessError(func, path, _):
   """Error handler for shutil.rmtree.
 
   Source: http://goo.gl/DEYNCT
 
   If the error is due to an access error (read only file), it attempts to add
   write permissions, then retries.
 
   If the error is for another reason it re-raises the error.
 
@@ skipping 85 matching lines @@
 def CheckRunGit(command, cwd=None):
   """Run a git subcommand, returning its output and return code. Asserts if
   the return code of the call is non-zero.
 
   Args:
     command: A list containing the args to git.
 
   Returns:
     A tuple of the output and return code.
   """
-  (output, return_code) = RunGit(command, cwd=cwd)
+  output, return_code = RunGit(command, cwd=cwd)
 
   assert not return_code, 'An error occurred while running'\
                           ' "git %s"' % ' '.join(command)
   return output
 
 
 def RunGit(command, cwd=None):
   """Run a git subcommand, returning its output and return code.
 
   Args:
@@ skipping 11 matching lines @@
   """Sets up a subdirectory 'bisect' and then retrieves a copy of the depot
   there using gclient.
 
   Args:
     opts: The options parsed from the command line through parse_args().
     custom_deps: A dictionary of additional dependencies to add to .gclient.
   """
   if CheckIfBisectDepotExists(opts):
     path_to_dir = os.path.join(os.path.abspath(opts.working_directory),
                                BISECT_DIR, 'src')
-    (output, _) = RunGit(['rev-parse', '--is-inside-work-tree'],
-                         cwd=path_to_dir)
+    output, _ = RunGit(['rev-parse', '--is-inside-work-tree'], cwd=path_to_dir)
     if output.strip() == 'true':
       # Before checking out master, cleanup up any leftover index.lock files.
       _CleanupPreviousGitRuns(path_to_dir)
       # Checks out the master branch, throws an exception if git command fails.
       CheckRunGit(['checkout', '-f', 'master'], cwd=path_to_dir)
   if not _CreateAndChangeToSourceDirectory(opts.working_directory):
     raise RuntimeError('Could not create bisect directory.')
 
   if not SetupGitDepot(opts, custom_deps):
     raise RuntimeError('Failed to grab source.')
@@ skipping 30 matching lines @@
 
   Returns:
     A tuple of the output and return code.
   """
   if cwd:
     original_cwd = os.getcwd()
     os.chdir(cwd)
 
   # On Windows, use shell=True to get PATH interpretation.
   shell = IsWindowsHost()
-  proc = subprocess.Popen(command, shell=shell, stdout=subprocess.PIPE,
+  proc = subprocess.Popen(
+      command, shell=shell, stdout=subprocess.PIPE,
       stderr=subprocess.STDOUT)
-  (output, _) = proc.communicate()
+  output, _ = proc.communicate()
 
   if cwd:
     os.chdir(original_cwd)
 
   return (output, proc.returncode)
 
 
 def IsStringInt(string_to_check):
   """Checks whether or not the given string can be converted to an int."""
   try:
@@ skipping 24 matching lines @@
     platform = os.environ.get('PROCESSOR_ARCHITECTURE')
   return platform and platform in ['AMD64', 'I64']
 
 
 def IsLinuxHost():
   return sys.platform.startswith('linux')
 
 
 def IsMacHost():
   return sys.platform.startswith('darwin')