Teach grit that file.svg is an SVG.

Teach grit that file.svg is an SVG.

When dropping the reliance of platform mime databases we also lost
support for the svg mime type. Readding it specifically.

Also added an explicit failure if something similar happens in the future.

BUG=383189
R=newt@chromium.org

Committed: https://code.google.com/p/grit-i18n/source/detail?r=169

[Daniel Bratell, 2014-06-11 15:23:51]

newt, can you please take a look at this fix to get spinners working in Chrome
OS again? I am not a committer so if it's ok I also need help committing.

[newt (away), 2014-06-11 18:31:26]

lgtm, though I'd also recommend removing FixupMimeType()

https://codereview.chromium.org/324383003/diff/1/grit/format/html_inline.py
File grit/format/html_inline.py (right):

https://codereview.chromium.org/324383003/diff/1/grit/format/html_inline.py#n...
grit/format/html_inline.py:125: mimetype =
FixupMimeType(platform_mimetype_guess)
looks like FixusMimeType() isn't needed anymore, since it just maps
'image/x-png' -> 'image/png', and platform_mimetype_guess will never be
'image/x-png' now that we call mimetypes.init() with any empty files list
(http://hg.python.org/cpython/file/2.7/Lib/mimetypes.py)

[Daniel Bratell, 2014-06-12 07:47:36]

newt, removed the Fixup that is no longer needed. Nice catch. Please take
another look (and if you can help land it, it would be very nice).

[newt (away), 2014-06-12 18:22:59]

lgtm.

landing this now...

[newt (away), 2014-06-12 18:36:22]

Committed patchset #2 manually as r169 (presubmit successful).