Add webp to supported image mime types if WEBP feature is enabled/used
https://bugs.webkit.org/show_bug.cgi?id=112819

Patch by Jeff Rogers <jrogers@rim.com> on 2013-04-09
Reviewed by Darin Adler.

Add WebP to list of supported image types in MIMETypeRegistry if enabled.

No new tests: WebP image decoding already covered by exisiting tests.

* platform/MIMETypeRegistry.cpp:
(WebCore::initializeSupportedImageMIMETypes):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148028 268f45cc-cd09-0410-ab3c-d52691b4dbfc