Register and select printer on click.

chrome/browser/ui/webui/print_preview/printer_capabilities.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/ui/webui/print_preview/printer_capabilities.h"
+
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "base/strings/string_piece.h"
+#include "base/values.h"
+#include "chrome/common/cloud_print/cloud_print_cdd_conversion.h"
+#include "chrome/common/crash_keys.h"
+#include "content/public/browser/browser_thread.h"
+#include "printing/backend/print_backend.h"
+
+namespace printing {
+
+const char kPrinterId[] = "printerId";
+const char kPrinterCapabilities[] = "capabilities";
+
+namespace {
+
+// Returns a Dictionary representing printer capabilities as CDD.
+std::unique_ptr<base::DictionaryValue>
+GetPrinterCapabilitiesOnBlockingPoolThread(const std::string& device_name) {
+  DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
+  DCHECK(!device_name.empty());
+
+  scoped_refptr<printing::PrintBackend> print_backend(

[Lei Zhang, 2016/11/03 23:41:46]

no printing:: in namespace printing :-P

[skau, 2016/11/04 19:28:59]

Done.

+      printing::PrintBackend::CreateInstance(nullptr));
+
+  VLOG(1) << "Get printer capabilities start for " << device_name;
+  crash_keys::ScopedPrinterInfo crash_key(
+      print_backend->GetPrinterDriverInfo(device_name));
+
+  std::unique_ptr<base::DictionaryValue> printer_info;
+  if (!print_backend->IsValidPrinter(device_name)) {
+    LOG(WARNING) << "Invalid printer " << device_name;
+    return nullptr;
+  }
+
+  printing::PrinterSemanticCapsAndDefaults info;
+  if (!print_backend->GetPrinterSemanticCapsAndDefaults(device_name, &info)) {
+    LOG(WARNING) << "Failed to get capabilities for " << device_name;
+    return nullptr;
+  }
+
+  std::unique_ptr<base::DictionaryValue> printer_capabilities =
+      cloud_print::PrinterSemanticCapsAndDefaultsToCdd(info);
+  if (!printer_capabilities) {
+    LOG(WARNING) << "Failed to convert capabilities for " << device_name;
+    return nullptr;
+  }
+
+  return printer_capabilities;
+}
+
+}  // namespace
+
+std::pair<std::string, std::string> GetPrinterNameAndDescription(
+    const printing::PrinterBasicInfo& printer) {
+#if defined(OS_MACOSX) || defined(OS_CHROMEOS)
+  // On Mac, |printer.printer_description| specifies the printer name and
+  // |printer.printer_name| specifies the device name / printer queue name.
+  // Chrome OS emulates the Mac behavior.
+  const std::string& real_name = printer.printer_description;
+  std::string real_description;
+  const auto it = printer.options.find(kDriverNameTagName);
+  if (it != printer.options.end())
+    real_description = it->second;
+  return std::make_pair(real_name, real_description);
+#else
+  return std::make_pair(printer.printer_name, printer.printer_description);
+#endif
+}
+
+std::unique_ptr<base::DictionaryValue> GetSettingsDictionary(
+    const std::string& device_name,
+    const printing::PrinterBasicInfo& basic_info) {
+  DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());

[Lei Zhang, 2016/11/03 23:41:46]

Does this still need to run on the blocking pool?

[skau, 2016/11/04 19:28:59]

Yes it does.  This calls GetPrinterCapabilitiesOnBlockingPoolThread directly.  I
would need to add a callback otherwise.

+
+  const auto printer_name_description =
+      GetPrinterNameAndDescription(basic_info);
+  const std::string& printer_name = printer_name_description.first;
+  const std::string& printer_description = printer_name_description.second;
+
+  auto printer_info = base::MakeUnique<base::DictionaryValue>();
+  printer_info->SetString(kPrinterId, device_name);
+  printer_info->SetString(printing::kSettingPrinterName, printer_name);
+  printer_info->SetString(printing::kSettingPrinterDescription,
+                          printer_description);
+
+  printer_info->Set(kPrinterCapabilities,
+                    GetPrinterCapabilitiesOnBlockingPoolThread(device_name));
+  return printer_info;
+}
+
+}  // namespace printing