Introduce a helper for OPENFILENAME struct to make certain logic testable.

ui/base/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/ui.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
 }
@@ skipping 221 matching lines @@
     "win/foreground_helper.cc",
     "win/foreground_helper.h",
     "win/hidden_window.cc",
     "win/hidden_window.h",
     "win/hwnd_subclass.cc",
     "win/hwnd_subclass.h",
     "win/internal_constants.cc",
     "win/internal_constants.h",
     "win/lock_state.cc",
     "win/lock_state.h",
+    "win/open_file_name_win.cc",
+    "win/open_file_name_win.h",
     "win/message_box_win.cc",
     "win/message_box_win.h",
     "win/mouse_wheel_util.cc",
     "win/mouse_wheel_util.h",
     "win/scoped_ole_initializer.cc",
     "win/scoped_ole_initializer.h",
     "win/shell.cc",
     "win/shell.h",
     "win/touch_input.cc",
     "win/touch_input.h",
@@ skipping 319 matching lines @@
       "../android/java/src/org/chromium/ui/base/LocalizationUtils.java",
       "../android/java/src/org/chromium/ui/base/ResourceBundle.java",
       "../android/java/src/org/chromium/ui/base/SelectFileDialog.java",
       "../android/java/src/org/chromium/ui/base/TouchDevice.java",
       "../android/java/src/org/chromium/ui/base/ViewAndroid.java",
       "../android/java/src/org/chromium/ui/base/WindowAndroid.java",
     ]
     jni_package = "base"
   }
 }