back out fix for 240644, attachment save dir handling, because its claimed it causes regressions, e.g., 395053

widget/src/windows/nsFilePicker.cpp

@@ -141,23 +141,12 @@ NS_IMETHODIMP nsFilePicker::ShowW(PRInt16 *aReturnVal)
   NS_NAMED_LITERAL_STRING(htmExt, "html");
   nsAutoString initialDir;
   if (mDisplayDirectory)
-  {
-    PRBool exists;
-    // checking this up front seems to behave much better than
-    // just trying to open  a file picker on a non-existent directory.
-    mDisplayDirectory->Exists(&exists);
-    if (exists)
-      mDisplayDirectory->GetPath(initialDir);
-  }
+    mDisplayDirectory->GetPath(initialDir);
 
   // If no display directory, re-use the last one.
   if(initialDir.IsEmpty()) {
     // Allocate copy of last used dir.
     initialDir = mLastUsedUnicodeDirectory;
-    // defaulting to cwd instead of whatever the file picker defaults to
-    // is a lot faster if that default dir doesn't exist.
-    if (initialDir.IsEmpty())
-      initialDir.AssignLiteral(".");
   }
 
   mUnicodeFile.Truncate();