Add a module to fetch builds from different types of builders.

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 523 matching lines @@
     True if the string can be converted to a float.
   """
   try:
     float(string_to_check)
     return True
   except ValueError:
     return False
 
 
 def IsWindowsHost():
-  """Checks whether or not the script is running on Windows.
-
-  Returns:
-    True if running on Windows.
-  """
+  """Checks whether or not the script is running on Windows."""
   return sys.platform == 'cygwin' or sys.platform.startswith('win')
 
 
 def Is64BitWindows():
   """Returns whether or not Windows is a 64-bit version.
 
   Returns:
     True if Windows is 64-bit, False if 32-bit.
   """
-  platform = os.environ['PROCESSOR_ARCHITECTURE']
-  try:
-    platform = os.environ['PROCESSOR_ARCHITEW6432']
-  except KeyError:
-    # Must not be running in WoW64, so PROCESSOR_ARCHITECTURE is correct
-    pass
-
-  return platform in ['AMD64', 'I64']
+  platform = os.environ.get('PROCESSOR_ARCHITEW6432')
+  if not platform:
+    # Must not be running in WoW64, so PROCESSOR_ARCHITECTURE is correct.
+    platform = os.environ.get('PROCESSOR_ARCHITECTURE')
+  return platform and platform in ['AMD64', 'I64']
 
 
 def IsLinuxHost():
-  """Checks whether or not the script is running on Linux.
-
-  Returns:
-    True if running on Linux.
-  """
+  """Checks whether or not the script is running on Linux."""
   return sys.platform.startswith('linux')
 
 
 def IsMacHost():
-  """Checks whether or not the script is running on Mac.
-
-  Returns:
-    True if running on Mac.
-  """
+  """Checks whether or not the script is running on Mac."""
   return sys.platform.startswith('darwin')