Remove enterprise serial number recovery feature

components/policy/proto/device_management_backend.proto

Index: components/policy/proto/device_management_backend.proto
diff --git a/components/policy/proto/device_management_backend.proto b/components/policy/proto/device_management_backend.proto
index 891baac806da6e418256641bd77647f3a0e42ea6..1597148bfb8121fdf2fc7083783935daa86f9097 100644
--- a/components/policy/proto/device_management_backend.proto
+++ b/components/policy/proto/device_management_backend.proto
@@ -187,6 +187,8 @@ message DeviceServiceApiAccessResponse {
 }
 
 message PolicyFetchRequest {
+  reserved 5, 10;

[Thiemo Nagel, 2017/05/24 09:17:42]

Hey Pavol, I've just realized that the "10" actually needs to go into
PolicyData.  Could you please fix?

[pmarko, 2017/05/24 09:42:11]

Good catch. Fix CL up:
https://chromium-review.googlesource.com/c/514082/

+
   // This is the policy type, which maps to D3 policy type internally.
   // By convention, we use "/" as separator to create policy namespace.
   // The policy type names are case insensitive.
@@ -220,12 +222,6 @@ message PolicyFetchRequest {
   // public key.
   optional int32 public_key_version = 4;
 
-  // Machine hardware id, such as serial number.
-  // This field is should be set only if the serial number for the device is
-  // missing from the server, as indicated by the valid_serial_number_missing
-  // field in the last policy fetch response.
-  optional string machine_id = 5;
-
   // This field is used for devices to send the additional ID to fetch settings.
   // Retrieving some settings requires more than just device or user ID.
   // For example, to retrieve public account, devices need to pass in
@@ -341,12 +337,6 @@ message PolicyData {
   }
   optional AssociationState state = 9 [default = ACTIVE];
 
-  // Indicates if the the server cannot find a valid serial number for the
-  // device.  If this flag is set, the device should send the valid serial
-  // number with a device policy fetch request.  Note that this only
-  // applies to device policy.
-  optional bool valid_serial_number_missing = 10;
-
   // Indicates which public account or extension/plug-in this policy data is
   // for. See PolicyFetchRequest.settings_entity_id for more details.
   optional string settings_entity_id = 11;