This patch prevents appending extension to filename derived from content disposition if it does not have one.

For example, in below case,
 Content-Type:text/plain;charset=UTF-8
 Content-Disposition:attachment; fileName = "ABC"

File is saved as "ABC" instead of "ABC.txt"

BUG=411200

Review URL: https://codereview.chromium.org/640713002

Cr-Commit-Position: refs/heads/master@{#301794}

1 files changed, 10 insertions, 2 deletions

diff --git a/net/base/filename_util_internal.cc b/net/base/filename_util_internal.cc
index 49b6a3d..cda7f62 100644
--- a/net/base/filename_util_internal.cc
+++ b/net/base/filename_util_internal.cc
@@ -229,11 +229,13 @@ base::string16 GetSuggestedFilenameImpl(
       FILE_PATH_LITERAL("download");
   std::string filename;  // In UTF-8
   bool overwrite_extension = false;
-
+  bool is_name_from_content_disposition = false;
   // Try to extract a filename from content-disposition first.
   if (!content_disposition.empty()) {
     HttpContentDisposition header(content_disposition, referrer_charset);
     filename = header.filename();
+    if (!filename.empty())
+      is_name_from_content_disposition = true;
   }
 
   // Then try to use the suggested name.
@@ -275,7 +277,13 @@ base::string16 GetSuggestedFilenameImpl(
   }
   replace_illegal_characters_callback.Run(&result_str, '-');
   base::FilePath result(result_str);
-  GenerateSafeFileName(mime_type, overwrite_extension, &result);
+  // extension should not appended to filename derived from
+  // content-disposition, if it does not have one.
+  // Hence mimetype and overwrite_extension values are not used.
+  if (is_name_from_content_disposition)
+    GenerateSafeFileName("", false, &result);
+  else
+    GenerateSafeFileName(mime_type, overwrite_extension, &result);
 
   base::string16 result16;
   if (!FilePathToString16(result, &result16)) {