[protosync] Server-side -> client

Sync server-side changes from cl/331193690.

Change-Id: I52afbafc55b5dc3804034acaaea08a31aa9cfd23
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2418660
Auto-Submit: Jit Yao Yap <jityao@google.com>
Reviewed-by: Alexander Hendrich <hendrich@chromium.org>
Commit-Queue: Alexander Hendrich <hendrich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810542}

components/policy/proto/device_management_backend.proto

@@ -686,6 +686,11 @@ message PolicyData {
   // UNSPECIFIED if not relevant.
   // This field should only be set for User Policy response.
   optional MetricsLogSegment metrics_log_segment = 35;
+
+  // This field will be populated with primary domain name for domain verified
+  // customer, and primary admin email for domainless customer. The client side
+  // will use this field to display who manages this device/browser/user.
+  optional string managed_by = 36;
 }
 
 message ClientActionRequired {