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

chrome/browser/download/download_prefs.cc

Index: chrome/browser/download/download_prefs.cc
diff --git a/chrome/browser/download/download_prefs.cc b/chrome/browser/download/download_prefs.cc
index e9e0b7681d696fe9685943a79cbe45a17994d675..9cd1406d2a7cf16807daca8bcefc45b2d248c389 100644
--- a/chrome/browser/download/download_prefs.cc
+++ b/chrome/browser/download/download_prefs.cc
@@ -60,18 +60,18 @@ void DownloadPrefs::RegisterUserPrefs(PrefService* prefs) {
                              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
@@ -82,7 +82,7 @@ void DownloadPrefs::RegisterUserPrefs(PrefService* prefs) {
         prefs::kDownloadDefaultDirectory);
     if (download_util::DownloadPathIsDangerous(current_download_dir)) {
       prefs->SetFilePath(prefs::kDownloadDefaultDirectory,
-                         default_download_path);
+                         default_download_dir);
     }
     prefs->SetBoolean(prefs::kDownloadDirUpgraded, true);
   }
@@ -135,6 +135,12 @@ void DownloadPrefs::ResetAutoOpen() {
   SaveAutoOpenState();
 }
 
+FilePath DownloadPrefs::GetDefaultDownloadDirectory() {
+  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();
@@ -153,6 +159,27 @@ void DownloadPrefs::SaveAutoOpenState() {
   prefs_->SetString(prefs::kDownloadExtensionsToOpen, extensions);
 }
 
+void DownloadPrefs::OverrideDefaultDownloadDirectory(

[Randy Smith (Not in Mondays), 2011/06/15 19:48:59]

I wince a bit at the behavior of these functions when you have nested instances
of ScopedDefaultDownloadDirectory--it basically doesn't work (the external
instance will have the original value, not the new value, after destruction of
the internal instance).  There's no need for nested functionality, but could you
comment indicating that it doesn't work?  (Or, if you feel moved, make it work
by creating a linked list/stack of ScopedDefaultDownloadDirectories that remove
themselves on destruction and returning the most recent one that was pushed on
the stack.  It's overkill, and you don't need to, it's just the behavior the
current interface implies to me.)

[Paweł Hajdan Jr., 2011/06/16 17:41:32]

A linked list/stack just for this is obviously an overkill. However, I think we
should prevent potential misuse by signaling failure when someone tries to
override an already overridden directory.

[haraken1, 2011/06/22 18:01:58]

I documented "Duplicate overriding is not allowed." at
ScopedDefaultDownloadDirectory() in download_test_util.h. I also put DCHECK()
here to check that the default download folder is not doubly overridden. 

+    const FilePath& override_default_download_dir) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  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 {