Don't treat zeroconf lpd records with port 0 as errors

The Bonjour spec requires printers to register their names with _printer
records even if they don't support LPD.  They indicate the lack of
support by registering a record with a port of 0.  Since this is an
expected event for this scenario, don't log it as an error.

Bug: None
Test: Watch chrome://device-log with local printer mDNS traffic
Change-Id: I15590c589c6e5ae44789b1353b638d247f9cce9e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5925508
Commit-Queue: Benjamin Gordon <bmgordon@chromium.org>
Reviewed-by: Nathan Muggli <nmuggli@google.com>
Cr-Commit-Position: refs/heads/main@{#1367812}

Author: yetamrra

chrome/browser/ash/printing/zeroconf_printer_detector.cc

@@ -181,9 +181,15 @@ bool ConvertToPrinter(const std::string& service_type,
     return false;
   }
   if (service_description.address.port() == 0) {
-    PRINTER_LOG(ERROR) << "Found zeroconf " << service_type
-                       << " printer named '" << service_description.service_name
-                       << "' with invalid port.";
+    // Bonjour printers are required to register the _printer._tcp name even if
+    // they don't support LPD.  If they don't support LPD, they use a port of 0
+    // to indicate this, so it is not an error.
+    if (service_type != ZeroconfPrinterDetector::kLpdServiceName) {
+      PRINTER_LOG(ERROR) << "Found zeroconf " << service_type
+                         << " printer named '"
+                         << service_description.service_name
+                         << "' with invalid port.";
+    }
     return false;
   }