Remove requirement that USB printers have a make/model metadata

chrome/browser/chromeos/printing/usb_printer_util.cc

Index: chrome/browser/chromeos/printing/usb_printer_util.cc
diff --git a/chrome/browser/chromeos/printing/usb_printer_util.cc b/chrome/browser/chromeos/printing/usb_printer_util.cc
index 28ae5c15e147464d74a227060c432c1ebfe28c42..5ba38bb56f6d3dfb5df8cf6f19fb0abfa75f639c 100644
--- a/chrome/browser/chromeos/printing/usb_printer_util.cc
+++ b/chrome/browser/chromeos/printing/usb_printer_util.cc
@@ -13,6 +13,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_piece.h"
+#include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chromeos/printing/printer_configuration.h"
@@ -146,8 +147,7 @@ std::string UsbPrinterDeviceDetailsAsString(const device::UsbDevice& device) {
 // from arbitrary devices.
 std::unique_ptr<Printer> UsbDeviceToPrinter(const device::UsbDevice& device) {
   // Preflight all required fields and log errors if we find something wrong.
-  if (device.vendor_id() == 0 || device.product_id() == 0 ||
-      device.manufacturer_string().empty() || device.product_string().empty()) {
+  if (device.vendor_id() == 0 || device.product_id() == 0) {
     LOG(ERROR) << "Failed to convert USB device to printer.  Fields were:\n"
                << UsbPrinterDeviceDetailsAsString(device);
     return nullptr;
@@ -156,9 +156,23 @@ std::unique_ptr<Printer> UsbDeviceToPrinter(const device::UsbDevice& device) {
   auto printer = base::MakeUnique<Printer>();
   printer->set_manufacturer(base::UTF16ToUTF8(device.manufacturer_string()));
   printer->set_model(base::UTF16ToUTF8(device.product_string()));
-  printer->set_display_name(base::StringPrintf("%s %s (USB)",
-                                               printer->manufacturer().c_str(),
-                                               printer->model().c_str()));
+
+  // Construct the display name by however much of the manufacturer/model
+  // information that we have available.
+  std::vector<std::string> display_name_parts;
+  if (!printer->manufacturer().empty()) {
+    display_name_parts.push_back(printer->manufacturer());
+  }
+  if (!printer->model().empty()) {
+    display_name_parts.push_back(printer->model());
+  }
+  if (display_name_parts.empty()) {
+    // If we have neither manufacturer nor model, just display the name as
+    // unknown.
+    display_name_parts.push_back("Unknown Printer");
+  }
+  display_name_parts.push_back("(USB)");
+  printer->set_display_name(base::JoinString(display_name_parts, " "));
   printer->set_description(printer->display_name());
   printer->set_uri(UsbPrinterUri(device));
   printer->set_id(UsbPrinterId(device));