format/chrome_messages_json.py does not encode multiline messages properly.

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Have a message spanning multiple lines.
2. Use GRIT to generate 'chrome_messages_json' output.
3. Open the generated json and observe that '\n' wasn't properly escaped.

What version of the product are you using? On what operating system?

http://grit-i18n.googlecode.com/svn/trunk@127

Windows 7

Please provide any additional information below.

I'll be uploading the fix for review shortly.

Original issue reported on code.google.com by alexeypa@chromium.org on 3 Jul 2013 at 5:21

[GoogleCodeExporter]

This should be fixed by r129.

Original comment by alexeypa@chromium.org on 8 Jul 2013 at 6:01