Ensure/document that the first parameter to the native messaging host is the origin

chrome/browser/extensions/api/messaging/native_process_launcher.cc

 // Copyright (c) 2012 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/extensions/api/messaging/native_process_launcher.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_split.h"
+#include "base/strings/stringprintf.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "build/build_config.h"
 #include "chrome/browser/extensions/api/messaging/native_messaging_host_manifest.h"
 #include "chrome/common/chrome_paths.h"
 #include "content/public/browser/browser_thread.h"
 #include "url/gurl.h"
 
 #if defined(OS_WIN)
 #include "ui/views/win/hwnd_util.h"
 #endif
 
 namespace extensions {
 
 namespace {
 
-#if defined(OS_WIN)
-// Name of the command line switch used to pass handle of the native view to
-// the native messaging host.
-const char kParentWindowSwitchName[] = "parent-window";
-#endif  // defined(OS_WIN)
-
 // Default implementation on NativeProcessLauncher interface.
 class NativeProcessLauncherImpl : public NativeProcessLauncher {
  public:
   NativeProcessLauncherImpl(bool allow_user_level_hosts,
                             intptr_t native_window);
   ~NativeProcessLauncherImpl() override;
 
   void Launch(const GURL& origin,
               const std::string& native_host_name,
               const LaunchedCallback& callback) const override;
@@ skipping 134 matching lines @@
   if (!base::PathExists(host_path)) {
     LOG(ERROR)
         << "Found manifest, but not the binary for native messaging host "
         << native_host_name << ". Host path specified in the manifest: "
         << host_path.AsUTF8Unsafe();
     PostErrorResult(callback, RESULT_NOT_FOUND);
     return;
   }
 
   base::CommandLine command_line(host_path);
+  // Note: The origin must be the first argument, so do not use AppendSwitch*
+  // hereafter because CommandLine inserts these switches before the other
+  // arguments.
   command_line.AppendArg(origin.spec());
 
   // Pass handle of the native view window to the native messaging host. This
   // way the host will be able to create properly focused UI windows.
 #if defined(OS_WIN)
-  command_line.AppendSwitchASCII(kParentWindowSwitchName,
-                                 base::Int64ToString(window_handle_));
+  command_line.AppendArg(
+      base::StringPrintf("--parent-window=%d", window_handle_));
 #endif  // !defined(OS_WIN)
 
   base::Process process;
   base::File read_file;
   base::File write_file;
   if (NativeProcessLauncher::LaunchNativeProcess(
           command_line, &process, &read_file, &write_file)) {
     PostResult(callback, std::move(process), std::move(read_file),
                std::move(write_file));
   } else {
@@ skipping 62 matching lines @@
   intptr_t window_handle = 0;
 #if defined(OS_WIN)
   window_handle = reinterpret_cast<intptr_t>(
       views::HWNDForNativeView(native_view));
 #endif
   return std::unique_ptr<NativeProcessLauncher>(
       new NativeProcessLauncherImpl(allow_user_level_hosts, window_handle));
 }
 
 }  // namespace extensions