[polymer] Merge of master into polymer10-migration

devil/devil/utils/battor_device_mapping.py

Index: devil/devil/utils/battor_device_mapping.py
diff --git a/devil/devil/utils/battor_device_mapping.py b/devil/devil/utils/battor_device_mapping.py
index dd12ce5aefa3d6394d734eddb987f4d6c5b445e8..a27433249c102ec9eed4d670be043eb64c332ce7 100644
--- a/devil/devil/utils/battor_device_mapping.py
+++ b/devil/devil/utils/battor_device_mapping.py
@@ -159,15 +159,25 @@ def GenerateSerialMap(hub_types=None):
 
   Args:
       hub_types: List of hub types to check for.
-      Defaults to ['plugable_7port']
+      Defaults to ['plugable_7port',
+                   'plugable_7port_usb3_part2',
+                   'plugable_7port_usb3_part3']
+      (see usb_hubs.py for details)
   """
   hub_types = [usb_hubs.GetHubType(x)
-               for x in hub_types or ['plugable_7port']]
+               for x in hub_types or ['plugable_7port',
+                                      'plugable_7port_usb3_part2',
+                                      'plugable_7port_usb3_part3']]
   devtree = find_usb_devices.GetBusNumberToDeviceTreeMap()
 
   # List of serial numbers in the system that represent BattOrs.
   battor_serials = list(GetBattorSerialNumbers(devtree))
 
+  # If there's only one BattOr in the system, then a serial number ma
+  # is not necessary.
+  if len(battor_serials) == 1:
+    return {}
+
   # List of dictionaries, one for each hub, that maps the physical
   # port number to the serial number of that hub. For instance, in a 2
   # hub system, this could return [{1:'ab', 2:'cd'}, {1:'jkl', 2:'xyz'}]