When the download folder does not exist, change the download folder to a user's "Downloads"

content/browser/download/save_package.cc

 // Copyright (c) 2011 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 "content/browser/download/save_package.h"
 
 #include <algorithm>
 
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ skipping 1127 matching lines @@
   FilePath::StringType mime_type(UTF8ToWide(contents_mime_type));
 #endif  // OS_WIN
   for (uint32 i = 0; i < ARRAYSIZE_UNSAFE(extensions); ++i) {
     if (mime_type == extensions[i].mime_type)
       return extensions[i].suggested_extension;
   }
   return FILE_PATH_LITERAL("");
 }
 
 void SavePackage::GetSaveInfo() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
   // Can't use tab_contents_ in the file thread, so get the data that we need
   // before calling to it.
   FilePath website_save_dir, download_save_dir;
   DCHECK(download_manager_);
   download_manager_->delegate()->GetSaveDir(
       tab_contents(), &website_save_dir, &download_save_dir);
   std::string mime_type = tab_contents()->contents_mime_type();
   std::string accept_languages =
       content::GetContentClient()->browser()->GetAcceptLangs(tab_contents());
 
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       NewRunnableMethod(this, &SavePackage::CreateDirectoryOnFileThread,
           website_save_dir, download_save_dir, mime_type, accept_languages));
 }
 
 void SavePackage::CreateDirectoryOnFileThread(
     const FilePath& website_save_dir,
     const FilePath& download_save_dir,
     const std::string& mime_type,
     const std::string& accept_langs) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+
+  FilePath default_downloads_dir =
+      download_util::GetDefaultDownloadDirectoryFromPathService();
   FilePath save_dir;
-  // If the default html/websites save folder doesn't exist...
-  if (!file_util::DirectoryExists(website_save_dir)) {
-    // If the default download dir doesn't exist, create it.
-    if (!file_util::DirectoryExists(download_save_dir))
-      file_util::CreateDirectory(download_save_dir);
-    save_dir = download_save_dir;
-  } else {
-    // If it does exist, use the default save dir param.
-    save_dir = website_save_dir;
-  }
+  // Ignores the returned value since the select file dialog should be
+  // displayed in any case.
+  download_util::ChooseSavableDirectory(
+      website_save_dir, download_save_dir, default_downloads_dir, &save_dir);
 
   bool can_save_as_complete = CanSaveAsComplete(mime_type);
   FilePath suggested_filename = GetSuggestedNameForSaveAs(
       can_save_as_complete, mime_type, accept_langs);
   FilePath::StringType pure_file_name =
       suggested_filename.RemoveExtension().BaseName().value();
   FilePath::StringType file_name_ext = suggested_filename.Extension();
 
   // Need to make sure the suggested file name is not too long.
   uint32 max_path = GetMaxPathLengthForDirectory(save_dir);
 
   if (GetSafePureFileName(save_dir, file_name_ext, max_path, &pure_file_name)) {
     save_dir = save_dir.Append(pure_file_name + file_name_ext);
   } else {
     // Cannot create a shorter filename. This will cause the save as operation
     // to fail unless the user pick a shorter name. Continuing even though it
     // will fail because returning means no save as popup for the user, which
     // is even more confusing. This case should be rare though.
     save_dir = save_dir.Append(suggested_filename);
   }
 
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       NewRunnableMethod(this, &SavePackage::ContinueGetSaveInfo, save_dir,
                         can_save_as_complete));
 }
 
 void SavePackage::ContinueGetSaveInfo(const FilePath& suggested_path,
                                       bool can_save_as_complete) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
   // The TabContents which owns this SavePackage may have disappeared during
   // the UI->FILE->UI thread hop of
   // GetSaveInfo->CreateDirectoryOnFileThread->ContinueGetSaveInfo.
   if (!tab_contents())
     return;
 
   download_manager_->delegate()->ChooseSavePath(
       AsWeakPtr(), suggested_path, can_save_as_complete);
 }
 
 // Called after the save file dialog box returns.
 void SavePackage::OnPathPicked(const FilePath& final_name,
                                SavePackageType type) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
   // Ensure the filename is safe.
   saved_main_file_path_ = final_name;
   // TODO(asanka): This call may block on IO and shouldn't be made
   // from the UI thread.  See http://crbug.com/61827.
   net::GenerateSafeFileName(tab_contents()->contents_mime_type(),
                             &saved_main_file_path_);
 
   saved_main_directory_path_ = saved_main_file_path_.DirName();
   save_type_ = type;
   if (save_type_ == SavePackage::SAVE_AS_COMPLETE_HTML) {
@@ skipping 47 matching lines @@
     StopObservation();
 }
 
 void SavePackage::FinalizeDownloadEntry() {
   DCHECK(download_);
   DCHECK(download_manager_);
 
   download_manager_->SavePageDownloadFinished(download_);
   StopObservation();
 }