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

tools/auto_bisect/bisect_utils.py

Index: tools/auto_bisect/bisect_utils.py
diff --git a/tools/auto_bisect/bisect_utils.py b/tools/auto_bisect/bisect_utils.py
index 330c4648508f91457200dbd3acbfd29efe0e75d2..f2a9ef6da3d49d4202210f424986985216d28a43 100644
--- a/tools/auto_bisect/bisect_utils.py
+++ b/tools/auto_bisect/bisect_utils.py
@@ -541,11 +541,7 @@ def IsStringFloat(string_to_check):
 
 
 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')
 
 
@@ -555,29 +551,18 @@ def Is64BitWindows():
   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')