Update the comments related to the host window in SelectFileDialogImplGTK

chrome/browser/ui/libgtk2ui/select_file_dialog_impl_gtk2.cc

 // Copyright (c) 2012 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/ui/libgtk2ui/select_file_dialog_impl_gtk2.h"
 
 #include <gtk/gtk.h>
 #include <stddef.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ skipping 98 matching lines @@
 void SelectFileDialogImplGTK::SelectFileImpl(
     Type type,
     const base::string16& title,
     const base::FilePath& default_path,
     const FileTypeInfo* file_types,
     int file_type_index,
     const base::FilePath::StringType& default_extension,
     gfx::NativeWindow owning_window,
     void* params) {
   type_ = type;
-  // |owning_window| can be null when user right-clicks on a downloadable item
-  // and chooses 'Open Link in New Tab' when 'Ask where to save each file
-  // before downloading.' preference is turned on. (http://crbug.com/29213)
   if (owning_window) {
     owning_window->AddObserver(this);
     parents_.insert(owning_window);
   }
 
   std::string title_string = base::UTF16ToUTF8(title);
 
   file_type_index_ = file_type_index;
   if (file_types)
     file_types_ = *file_types;
@@ skipping 278 matching lines @@
   std::map<GtkWidget*, void*>::iterator iter = params_map_.find(dialog);
   DCHECK(iter != params_map_.end());
   void* params = iter->second;
   params_map_.erase(iter);
   return params;
 }
 
 void SelectFileDialogImplGTK::FileDialogDestroyed(GtkWidget* dialog) {
   dialogs_.erase(dialog);
 
-  // Parent may be NULL in a few cases: 1) on shutdown when
-  // AllBrowsersClosed() trigger this handler after all the browser
-  // windows got destroyed, or 2) when the parent tab has been opened by
-  // 'Open Link in New Tab' context menu on a downloadable item and
-  // the tab has no content (see the comment in SelectFile as well).
+  // |parent| can be NULL when closing the host window
+  // while opening the file-picker.
   aura::Window* parent = GetAuraTransientParent(dialog);
   if (!parent)
     return;
   std::set<aura::Window*>::iterator iter = parents_.find(parent);
   if (iter != parents_.end()) {
     (*iter)->RemoveObserver(this);
     parents_.erase(iter);
   } else {
     NOTREACHED();
   }
@@ skipping 106 matching lines @@
   g_free(filename);
   if (pixbuf) {
     gtk_image_set_from_pixbuf(GTK_IMAGE(preview_), pixbuf);
     g_object_unref(pixbuf);
   }
   gtk_file_chooser_set_preview_widget_active(GTK_FILE_CHOOSER(chooser),
                                              pixbuf ? TRUE : FALSE);
 }
 
 }  // namespace libgtk2ui