[Nearby] Update ContactRecord proto

Since cl/337200290, the Nearby Share server returns both Google contacts
and device contacts in the ListContactPeople RPC response. That update
labels every contact with a Google-, device-, or unknown-contact type.
The burden is on the client to filter by type if desired.

We update the proto here, but do not make use of the new contact type
field.

Bug: 1143680
Change-Id: Icae01e5066f89debe80ea7e66bb5ebd022cae0ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2507452
Auto-Submit: Josh Nohle <nohle@chromium.org>
Commit-Queue: James Vecore <vecore@google.com>
Reviewed-by: James Vecore <vecore@google.com>
Cr-Commit-Position: refs/heads/master@{#822201}

chrome/browser/nearby_sharing/proto/rpc_resources.proto

@@ -80,8 +80,20 @@ message Contact {
 }
 
 // A contact record from People backend.
-// NextId=5
+// NextId=6
 message ContactRecord {
+  // The type of the ContactRecord.
+  enum Type {
+    // The source of the contact is unknown.
+    UNKNOWN = 0;
+
+    // The source of the contact is from google (i.e. google.com/contacts).
+    GOOGLE_CONTACT = 1;
+
+    // The source of the contact is from a device.
+    DEVICE_CONTACT = 2;
+  }
+
   // The stable id of this contact record.
   string id = 1;
 
@@ -94,6 +106,9 @@ message ContactRecord {
 
   // A list of phone numbers and emails under this contact record.
   repeated Contact.Identifier identifiers = 4;
+
+  // The type of the ContactRecord.
+  Type type = 5;
 }
 
 // A ShareTarget is a potential destination of a share.