refactor: move GetPrinterList off WebContents (#26518)

shell/browser/api/electron_api_printing.cc

@@ -0,0 +1,77 @@
+// Copyright (c) 2020 Slack Technologies, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "base/threading/thread_restrictions.h"
+#include "chrome/browser/browser_process.h"
+#include "gin/converter.h"
+#include "printing/buildflags/buildflags.h"
+#include "shell/common/gin_helper/dictionary.h"
+#include "shell/common/node_includes.h"
+
+#if BUILDFLAG(ENABLE_PRINTING)
+#include "printing/backend/print_backend.h"
+#endif
+
+namespace gin {
+
+#if BUILDFLAG(ENABLE_PRINTING)
+template <>
+struct Converter<printing::PrinterBasicInfo> {
+  static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
+                                   const printing::PrinterBasicInfo& val) {
+    gin_helper::Dictionary dict = gin::Dictionary::CreateEmpty(isolate);
+    dict.Set("name", val.printer_name);
+    dict.Set("displayName", val.display_name);
+    dict.Set("description", val.printer_description);
+    dict.Set("status", val.printer_status);
+    dict.Set("isDefault", val.is_default ? true : false);
+    dict.Set("options", val.options);
+    return dict.GetHandle();
+  }
+};
+#endif
+
+}  // namespace gin
+
+namespace electron {
+
+namespace api {
+
+#if BUILDFLAG(ENABLE_PRINTING)
+printing::PrinterList GetPrinterList() {
+  printing::PrinterList printers;
+  auto print_backend = printing::PrintBackend::CreateInstance(
+      g_browser_process->GetApplicationLocale());
+  {
+    // TODO(deepak1556): Deprecate this api in favor of an
+    // async version and post a non blocing task call.
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+    print_backend->EnumeratePrinters(&printers);
+  }
+  return printers;
+}
+#endif
+
+}  // namespace api
+
+}  // namespace electron
+
+namespace {
+
+using electron::api::GetPrinterList;
+
+void Initialize(v8::Local<v8::Object> exports,
+                v8::Local<v8::Value> unused,
+                v8::Local<v8::Context> context,
+                void* priv) {
+  v8::Isolate* isolate = context->GetIsolate();
+  gin_helper::Dictionary dict(isolate, exports);
+#if BUILDFLAG(ENABLE_PRINTING)
+  dict.SetMethod("getPrinterList", base::BindRepeating(&GetPrinterList));
+#endif
+}
+
+}  // namespace
+
+NODE_LINKED_MODULE_CONTEXT_AWARE(electron_browser_printing, Initialize)