Preserve modification timestamp when zipping files.

third_party/zlib/google/zip_reader.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 "third_party/zlib/google/zip_reader.h"
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 213 matching lines @@
       break;
     } else if (num_bytes_read > 0) {
       // Some data is read. Write it to the output file.
       if (num_bytes_read != stream.WriteSync(buf, num_bytes_read)) {
         success = false;
         break;
       }
     }
   }
 
+  stream.CloseSync();
   unzCloseCurrentFile(zip_file_);
+
+  if (current_entry_info()->last_modified() != base::Time::UnixEpoch())
+    base::TouchFile(output_file_path,
+                    base::Time::Now(),
+                    current_entry_info()->last_modified());
+
   return success;
 }
 
 bool ZipReader::ExtractCurrentEntryIntoDirectory(
     const base::FilePath& output_directory_path) {
   DCHECK(current_entry_info_.get());
 
   base::FilePath output_file_path = output_directory_path.Append(
       current_entry_info()->file_path());
   return ExtractCurrentEntryToFilePath(output_file_path);
@@ skipping 56 matching lines @@
 }
 
 void ZipReader::Reset() {
   zip_file_ = NULL;
   num_entries_ = 0;
   reached_end_ = false;
   current_entry_info_.reset();
 }
 
 }  // namespace zip