Added callback to DownloadUrl() so we can find download failures.

content/test/mock_download_manager.h

Index: content/test/mock_download_manager.h
diff --git a/content/test/mock_download_manager.h b/content/test/mock_download_manager.h
index d5ca6d09645eefbf541f8613af0c45e6248c0253..fb078e34c3d81457e7c6358ef8f375bd8ee61848 100644
--- a/content/test/mock_download_manager.h
+++ b/content/test/mock_download_manager.h
@@ -51,13 +51,15 @@ class MockDownloadManager : public content::DownloadManager {
                                            base::Time remove_end));
   MOCK_METHOD1(RemoveDownloads, int(base::Time remove_begin));
   MOCK_METHOD0(RemoveAllDownloads, int());
-  MOCK_METHOD7(DownloadUrl, void(const GURL& url,
-                                 const GURL& referrer,
-                                 const std::string& referrer_encoding,
-                                 bool prefer_cache,
-                                 int64 post_id,
-                                 const DownloadSaveInfo& save_info,
-                                 content::WebContents* web_contents));
+  MOCK_METHOD8(DownloadUrl,
+      void(const GURL& url,
+           const GURL& referrer,
+           const std::string& referrer_encoding,
+           bool prefer_cache,
+           int64 post_id,
+           const DownloadSaveInfo& save_info,
+           content::WebContents* web_contents,
+           const DownloadManager::OnStartedCallback& callback));
   MOCK_METHOD1(AddObserver, void(Observer* observer));
   MOCK_METHOD1(RemoveObserver, void(Observer* observer));
   MOCK_METHOD1(OnPersistentStoreQueryComplete, void(