Fix use-after-scope issues with incorrect usage of ManifestParser.

content/renderer/manifest/manifest_manager.cc

Index: content/renderer/manifest/manifest_manager.cc
diff --git a/content/renderer/manifest/manifest_manager.cc b/content/renderer/manifest/manifest_manager.cc
index d54e41a9efe28fbfe689b7dc9e599b20c6dc2a9d..b6d3b819087515bd813fc447ee166ba8c45e56e8 100644
--- a/content/renderer/manifest/manifest_manager.cc
+++ b/content/renderer/manifest/manifest_manager.cc
@@ -150,7 +150,9 @@ void ManifestManager::OnManifestFetchComplete(
   }
 
   ManifestUmaUtil::FetchSucceeded();
-  ManifestParser parser(data, response.url(), document_url);
+  GURL response_url = response.url();
+  base::StringPiece data_piece(data);
+  ManifestParser parser(data_piece, response_url, document_url);
   parser.Parse();
 
   fetcher_.reset();