Failed offline snapshots won't erase a successful one from the same page load.

components/offline_pages/offline_page_test_archiver.h

 // Copyright 2015 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.
 
 #ifndef COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_TEST_ARCHIVER_H_
 #define COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_TEST_ARCHIVER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 32 matching lines @@
       int64_t size_to_report,
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
   ~OfflinePageTestArchiver() override;
 
   // OfflinePageArchiver implementation:
   void CreateArchive(const base::FilePath& archives_dir,
                      int64_t archive_id,
                      const CreateArchiveCallback& callback) override;
 
   // Completes the creation of archive. Should be used with |set_delayed| set to
-  // ture.
+  // true.
   void CompleteCreateArchive();
 
   // When set to true, |CompleteCreateArchive| should be called explicitly for
   // the process to finish.
   // TODO(fgorski): See if we can move this to the constructor.
   void set_delayed(bool delayed) { delayed_ = delayed; }
 
   // Allows to explicitly specify a file name for the tests.
   // TODO(fgorski): See if we can move this to the constructor.
   void set_filename(const base::FilePath& filename) { filename_ = filename; }
@@ skipping 13 matching lines @@
   base::string16 result_title_;
   CreateArchiveCallback callback_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(OfflinePageTestArchiver);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_TEST_ARCHIVER_H_