Code refactoring: move mimeTypeFromUTITree to a separate file.

Code refactoring: move mimeTypeFromUTITree to a separate file.
https://bugs.webkit.org/show_bug.cgi?id=90619

We should move UTI handling related code to a separate file.

Patch by Yongjun Zhang <yongjun_zhang@apple.com> on 2012-07-05
Reviewed by David Kilzer.

* WebCore.xcodeproj/project.pbxproj: Add UTIUtilities.h/UTIUtilities.mm to xcode project, and drive-by fix
    that happened when editing the Xcode project file.
* platform/network/mac/UTIUtilities.h: Added.
(WebCore):
* platform/network/mac/UTIUtilities.mm: Added.  move mimeTypeFromUTITree to UTIUtilities.mm.
(WebCore):
(WebCore::mimeTypeFromUTITree):
* platform/network/mac/WebCoreURLResponse.mm: include UTIUtilities.h to use mimeTypeFromUTITree.
(WebCore):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@121923 268f45cc-cd09-0410-ab3c-d52691b4dbfc