Remove download_manager_ CHECK in ~SavePackage

download_manager_ can non-null if SavePackage is created and destroyed without Init() being called.
This CHECK was originally introduced when SavePackage was an observer of the DownloadManager.

BUG=91884
TEST=NONE
Review URL: http://codereview.chromium.org/7599001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@95851 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/download/save_package.cc

@@ -192,8 +192,7 @@ SavePackage::~SavePackage() {
     Cancel(true);
   }
 
-  // We should no longer be observing the DownloadManager at this point.
-  CHECK(!download_manager_);
+  // We should no longer be observing the DownloadItem at this point.
   CHECK(!download_);
 
   DCHECK(all_save_items_count_ == (waiting_item_queue_.size() +