Allow dragging a download only after the download is complete.

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 e1da54d07532036dc482dfd47557a1a9d9940123..f102350d47781fc16c351567babc78432f889cee 100644
--- a/chrome/browser/ui/gtk/download/download_item_gtk.cc
+++ b/chrome/browser/ui/gtk/download/download_item_gtk.cc
@@ -458,7 +458,10 @@ void DownloadItemGtk::OnLoadSmallIconComplete(gfx::Image* image) {
 
 void DownloadItemGtk::OnLoadLargeIconComplete(gfx::Image* image) {
   icon_large_ = image;
-  DownloadItemDrag::SetSource(body_.get(), download(), icon_large_);
+  if (download()->IsComplete())
+    DownloadItemDrag::SetSource(body_.get(), download(), icon_large_);
+  // Else, the download will be made draggable once an OnDownloadUpdated()
+  // notification is received with download->IsComplete().
 }
 
 void DownloadItemGtk::LoadIcon() {