Create the download folder if it doesn't exist.

chrome/common/chrome_paths.cc

 // Copyright (c) 2006-2008 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/common/chrome_paths.h"
 
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
@@ skipping 78 matching lines @@
 #endif
       break;
     case chrome::DIR_USER_DOCUMENTS:
       if (!GetUserDocumentsDirectory(&cur))
         return false;
       create_dir = true;
       break;
     case chrome::DIR_DEFAULT_DOWNLOADS:
       if (!GetUserDownloadsDirectory(&cur))
         return false;
+      create_dir = true;
       break;
     case chrome::DIR_CRASH_DUMPS:
       // The crash reports are always stored relative to the default user data
       // directory.  This avoids the problem of having to re-initialize the
       // exception handler after parsing command line options, which may
       // override the location of the app's profile directory.
       if (!GetDefaultUserDataDirectory(&cur))
         return false;
       cur = cur.Append(FILE_PATH_LITERAL("Crash Reports"));
       create_dir = true;
@@ skipping 95 matching lines @@
   return true;
 }
 
 // This cannot be done as a static initializer sadly since Visual Studio will
 // eliminate this object file if there is no direct entry point into it.
 void RegisterPathProvider() {
   PathService::RegisterProvider(PathProvider, PATH_START, PATH_END);
 }
 
 }  // namespace chrome