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

chrome/browser/download/download_prefs.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 "chrome/browser/download/download_prefs.h"
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/string_split.h"
 #include "base/string_util.h"
@@ skipping 42 matching lines @@
   prefs->RegisterStringPref(prefs::kDownloadExtensionsToOpen,
                             "",
                             PrefService::UNSYNCABLE_PREF);
   prefs->RegisterBooleanPref(prefs::kDownloadDirUpgraded,
                              false,
                              PrefService::UNSYNCABLE_PREF);
   prefs->RegisterIntegerPref(prefs::kSaveFileType,
                              SavePackage::SAVE_AS_COMPLETE_HTML,
                              PrefService::UNSYNCABLE_PREF);
 
-  // The default download path is userprofile\download.
-  const FilePath& default_download_path =
-      download_util::GetDefaultDownloadDirectory();
+  // The user's default "Downloads" folder.
+  FilePath default_download_dir =
+      download_util::GetDefaultDownloadDirectoryFromPathService();
   prefs->RegisterFilePathPref(prefs::kDownloadDefaultDirectory,
-                              default_download_path,
+                              default_download_dir,
                               PrefService::UNSYNCABLE_PREF);
 
 #if defined(OS_CHROMEOS)
   // Ensure that the download directory specified in the preferences exists.
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
-      NewRunnableFunction(&file_util::CreateDirectory, default_download_path));
+      NewRunnableFunction(&file_util::CreateDirectory, default_download_dir));
 #endif  // defined(OS_CHROMEOS)
 
   // If the download path is dangerous we forcefully reset it. But if we do
   // so we set a flag to make sure we only do it once, to avoid fighting
   // the user if he really wants it on an unsafe place such as the desktop.
   if (!prefs->GetBoolean(prefs::kDownloadDirUpgraded)) {
     FilePath current_download_dir = prefs->GetFilePath(
         prefs::kDownloadDefaultDirectory);
     if (download_util::DownloadPathIsDangerous(current_download_dir)) {
       prefs->SetFilePath(prefs::kDownloadDefaultDirectory,
-                         default_download_path);
+                         default_download_dir);
     }
     prefs->SetBoolean(prefs::kDownloadDirUpgraded, true);
   }
 }
 
 bool DownloadPrefs::PromptForDownload() const {
   // If the DownloadDirectory policy is set, then |prompt_for_download_| should
   // always be false.
   DCHECK(!download_path_.IsManaged() || !prompt_for_download_.GetValue());
   return *prompt_for_download_;
@@ skipping 32 matching lines @@
   extension.erase(0, 1);
   auto_open_.erase(extension);
   SaveAutoOpenState();
 }
 
 void DownloadPrefs::ResetAutoOpen() {
   auto_open_.clear();
   SaveAutoOpenState();
 }
 
+FilePath DownloadPrefs::GetDefaultDownloadDirectory() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  if (!override_default_download_dir_.empty())
+    return override_default_download_dir_;
+  return download_util::GetDefaultDownloadDirectoryFromPathService();
+}
+
 void DownloadPrefs::SaveAutoOpenState() {
   std::string extensions;
   for (AutoOpenSet::iterator it = auto_open_.begin();
        it != auto_open_.end(); ++it) {
 #if defined(OS_POSIX)
     std::string this_extension = *it;
 #elif defined(OS_WIN)
     // TODO(phajdan.jr): Why we're using Sys conversion here, but not in ctor?
     std::string this_extension = base::SysWideToUTF8(*it);
 #endif
     extensions += this_extension + ":";
   }
   if (!extensions.empty())
     extensions.erase(extensions.size() - 1);
 
   prefs_->SetString(prefs::kDownloadExtensionsToOpen, extensions);
 }
 
+void DownloadPrefs::OverrideDefaultDownloadDirectory(
+    const FilePath& override_default_download_dir) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // Duplicate overriding is not allowed.
+  DCHECK(override_default_download_dir_.empty());
+
+  FilePath default_download_dir = GetDefaultDownloadDirectory();
+  if (*download_path_ == default_download_dir)
+    download_path_.SetValue(override_default_download_dir);
+
+  override_default_download_dir_ = override_default_download_dir;
+}
+
+void DownloadPrefs::UnOverrideDefaultDownloadDirectory() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  DCHECK(!override_default_download_dir_.empty());
+  override_default_download_dir_.clear();
+
+  FilePath default_download_dir = GetDefaultDownloadDirectory();
+  download_path_.SetValue(default_download_dir);
+}
+
 bool DownloadPrefs::AutoOpenCompareFunctor::operator()(
     const FilePath::StringType& a,
     const FilePath::StringType& b) const {
   return FilePath::CompareLessIgnoreCase(a, b);
 }