(Cross-submitted from http://code.google.com/p/chromium/issues/detail?id=91159)
What steps will reproduce the problem?
1. Create a blob of any media type.
2. Write the blob to a file without a filename extension or a not well-known filename extension.
3. Navigate to the filesystem: URL.
What is the expected result?
The media type of the file is the media type that was assigned to the blob that was written to the file. If the blob had no media type, the media type of the file is derived from its filename extension.
What happens instead?
The media type of the file is derived only from its filename extension.