Mandoline: let html_viewer handle more contents
- Let html_viewer handle 'text/plain'.
- When a URL fetch results in 4XX/5XX status code, don't drop the response.
If the mime type is 'text/html' or 'text/plain', the response will be
rendered by html_viewer.
- AboutFetcher returns 404 for about: URLs other than about:blank.
BUG=None
Review URL: https://codereview.chromium.org/1342093002
Cr-Commit-Position: refs/heads/master@{#349138}
CrOS-Libchrome-Original-Commit: faf4512218eb08a205e31bde8b5dba84e9b58056
6 files changed