Use DownloadItemModel for storing chrome/ specific UI data for DownloadItems.

chrome/browser/ui/browser.cc

Index: chrome/browser/ui/browser.cc
diff --git a/chrome/browser/ui/browser.cc b/chrome/browser/ui/browser.cc
index 187682db841f6f359bb54a9f76e7c1462cf504cf..47dd0f74988eb985af0ebc04a7b2a1a266c042bb 100644
--- a/chrome/browser/ui/browser.cc
+++ b/chrome/browser/ui/browser.cc
@@ -1479,7 +1479,8 @@ int Browser::GetExtraRenderViewHeight() const {
 
 void Browser::OnStartDownload(WebContents* source,
                               content::DownloadItem* download) {
-  if (!download_util::ShouldShowInShelf(download))
+  scoped_ptr<DownloadItemModel> download_model(new DownloadItemModel(download));
+  if (!download_model->ShouldShowInShelf())
     return;
 
   WebContents* constrained = GetConstrainingWebContents(source);
@@ -1494,7 +1495,7 @@ void Browser::OnStartDownload(WebContents* source,
 
   // GetDownloadShelf creates the download shelf if it was not yet created.
   DownloadShelf* shelf = window()->GetDownloadShelf();
-  shelf->AddDownload(new DownloadItemModel(download));
+  shelf->AddDownload(download_model.release());

[sky, 2012/12/10 18:04:52]

Would be nice to use download_model.Pass() here. Maybe in a future patch?

[asanka, 2012/12/10 18:52:14]

I'll do this in a follow-up CL next.

   // Don't show the animation for "Save file" downloads.
   // For non-theme extensions, we don't show the download animation.
   // Show animation in same window as the download shelf. Download shelf