Add interface to CancelableRequest that allows use of base::Callback<>.

chrome/browser/ui/gtk/download/download_item_gtk.cc

Index: chrome/browser/ui/gtk/download/download_item_gtk.cc
diff --git a/chrome/browser/ui/gtk/download/download_item_gtk.cc b/chrome/browser/ui/gtk/download/download_item_gtk.cc
index a908be5430eca2e6206a8b9209b6a3e78b0f0014..ea3a30e732313d4dbb10eab95cef22c82ae785f1 100644
--- a/chrome/browser/ui/gtk/download/download_item_gtk.cc
+++ b/chrome/browser/ui/gtk/download/download_item_gtk.cc
@@ -461,10 +461,12 @@ void DownloadItemGtk::LoadIcon() {
   icon_filepath_ = get_download()->GetUserVerifiedFilePath();
   im->LoadIcon(icon_filepath_,
                IconLoader::SMALL, &icon_consumer_,
-               NewCallback(this, &DownloadItemGtk::OnLoadSmallIconComplete));
+               base::Bind(&DownloadItemGtk::OnLoadSmallIconComplete,
+                          base::Unretained(this)));
   im->LoadIcon(icon_filepath_,
                IconLoader::LARGE, &icon_consumer_,
-               NewCallback(this, &DownloadItemGtk::OnLoadLargeIconComplete));
+               base::Bind(&DownloadItemGtk::OnLoadLargeIconComplete,
+                          base::Unretained(this)));
 }
 
 void DownloadItemGtk::UpdateTooltip() {