Move download stuff from download helper back to TabContents. This is basically a revert of r8576...

chrome/browser/prerender/prerender_contents.cc

Index: chrome/browser/prerender/prerender_contents.cc
===================================================================
--- chrome/browser/prerender/prerender_contents.cc	(revision 92561)
+++ chrome/browser/prerender/prerender_contents.cc	(working copy)
@@ -517,18 +517,6 @@
     render_view_host_observer_->set_prerender_contents(NULL);
 }
 
-bool PrerenderContents::CanDownload(int request_id) {
-  Destroy(FINAL_STATUS_DOWNLOAD);
-  // Cancel the download.
-  return false;
-}
-
-void PrerenderContents::OnStartDownload(DownloadItem* download,
-                                        TabContentsWrapper* tab) {
-  // Prerendered pages should never be able to download files.
-  NOTREACHED();
-}
-
 base::ProcessMetrics* PrerenderContents::MaybeGetProcessMetrics() {
   if (process_metrics_.get() == NULL) {
     // If a PrenderContents hasn't started prerending, don't be fully formed.