Scaffold an executable

net/BUILD.gn

@@ -2185,6 +2185,16 @@ static_library("test_support") {
   }
 }
 
+target(final_executable_type, "downloader") {
+    testonly = true
+    sources = [
+      "tools/downloader/downloader.cc"
+    ]
+    deps = [
+      ":net",
+    ]
+  }
+
 if (!is_ios && !is_android && !use_cobalt_customizations) {
   executable("cert_verify_tool") {
     testonly = true

net/tools/downloader/downloader.cc

@@ -0,0 +1,43 @@
+#include <iostream>
+#include "base/at_exit.h"
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/task/single_thread_task_executor.h"
+
+
+namespace downloader {
+void PrintUsage(std::ostream* stream) {
+  *stream << "Usage: downloader <url>" << std::endl;
+}
+
+bool Main(int argc, char** argv) {
+  base::AtExitManager at_exit_manager;
+
+  logging::LoggingSettings settings;
+  settings.logging_dest =
+      logging::LOG_TO_SYSTEM_DEBUG_LOG | logging::LOG_TO_STDERR;
+  logging::InitLogging(settings);
+
+  base::CommandLine::Init(argc, argv);
+  const base::CommandLine& command_line =
+      *base::CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch("help")) {
+    PrintUsage(&std::cout);
+    return true;
+  }
+  if (command_line.HasSwitch("url")) {
+    std::string url = command_line.GetSwitchValueASCII("url");
+    LOG(ERROR) << "URL URL :" << url;
+  }
+
+  // Just make the main task executor the network loop.
+  base::SingleThreadTaskExecutor io_task_executor(base::MessagePumpType::IO);
+
+
+  LOG(ERROR) << "Hey";
+}
+}  // namespace downloader
+
+int main(int argc, char** argv) {
+  return !downloader::Main(argc, argv);
+}