Load 16x16 icons for shelf.

chrome/browser/cocoa/download_item_mac.mm

Index: chrome/browser/cocoa/download_item_mac.mm
diff --git a/chrome/browser/cocoa/download_item_mac.mm b/chrome/browser/cocoa/download_item_mac.mm
index 453e52c99b99a34727c602abe4d2667c9cd1fe28..e025d06cea692de9839e42be5e0347465b1ac596 100644
--- a/chrome/browser/cocoa/download_item_mac.mm
+++ b/chrome/browser/cocoa/download_item_mac.mm
@@ -70,7 +70,7 @@ void DownloadItemMac::LoadIcon() {
   }
 
   // The icon isn't cached, load it asynchronously.
-  icon_manager->LoadIcon(file, IconLoader::NORMAL, &icon_consumer_,
+  icon_manager->LoadIcon(file, IconLoader::SMALL, &icon_consumer_,
                          NewCallback(this,
                                      &DownloadItemMac::OnExtractIconComplete));
 }