Prefer Product_S/N when reading the serial number for enterprise enrollment.

This is effectively a partial revert of http://codereview.chromium.org/10542072/ for Lumpy devices, all other models remain unaffected because they don't have both the serial_number and Product_S/N keys in VPD.

Background: The serial_number VPD key (which would be the right source in an ideal world) returns a checksum-suffixed serial number on Lumpy devices that includes a trailing checksum character. That unfortunately causes trouble with the server side, which uses the non-suffixed serial number.

BUG=chromium:142681, chromium-os:31652
TEST=Check serial number reported on enterprise enrollment and used for auto-enrollment on Lumpy.

Review URL: https://chromiumcodereview.appspot.com/10830316

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151557 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/policy/browser_policy_connector.cc

@@ -87,9 +87,20 @@ const char kMachineInfoSystemHwqual[] = "hardware_class";
 // in the "serial_number" key for v2+ VPDs. However, legacy devices used a
 // different keys to report their serial number, which we fall back to if
 // "serial_number" is not present.
+//
+// Product_S/N is still special-cased due to inconsistencies with serial
+// numbers on Lumpy devices: On these devices, serial_number is identical to
+// Product_S/N with an appended checksum. Unfortunately, the sticker on the
+// packaging doesn't include that checksum either (the sticker on the device
+// does though!). The former sticker is the source of the serial number used by
+// device management service, so we prefer Product_S/N over serial number to
+// match the server.
+//
+// TODO(mnissler): Move serial_number back to the top once the server side uses
+// the correct serial number.
 const char* kMachineInfoSerialNumberKeys[] = {
+  "Product_S/N",   // Lumpy/Alex devices
   "serial_number", // VPD v2+ devices
-  "Product_S/N",   // Alex
   "Product_SN",    // Mario
   "sn",            // old ZGB devices (more recent ones use serial_number)
 };