Allow dragging a download only after the download is complete.

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

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/gtk/download/download_item_gtk.h"
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/debug/trace_event.h"
 #include "base/metrics/histogram.h"
@@ skipping 440 matching lines @@
 
 // Icon loading functions.
 
 void DownloadItemGtk::OnLoadSmallIconComplete(gfx::Image* image) {
   icon_small_ = image;
   gtk_widget_queue_draw(progress_area_.get());
 }
 
 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() {
   cancelable_task_tracker_.TryCancelAll();
   IconManager* im = g_browser_process->icon_manager();
   icon_filepath_ = download()->GetUserVerifiedFilePath();
   im->LoadIcon(icon_filepath_,
                IconLoader::SMALL,
                base::Bind(&DownloadItemGtk::OnLoadSmallIconComplete,
                           base::Unretained(this)),
@@ skipping 448 matching lines @@
   download()->DangerousDownloadValidated();
 }
 
 void DownloadItemGtk::OnDangerousDecline(GtkWidget* button) {
   UMA_HISTOGRAM_LONG_TIMES("clickjacking.discard_download",
                            base::Time::Now() - creation_time_);
   if (download()->IsPartialDownload())
     download()->Cancel(true);
   download()->Delete(DownloadItem::DELETE_DUE_TO_USER_DISCARD);
 }