Reviewed by Antti Koivisto.

        https://bugs.webkit.org/show_bug.cgi?id=23999
        Split off MIME type parsing into its own class.

        * GNUmakefile.am: Added ContentType sources.
        * WebCore.pro: Ditto.
        * WebCore.scons: Ditto.
        * WebCore.vcproj/WebCore.vcproj: Ditto.
        * WebCore.xcodeproj/project.pbxproj: Ditto.
        * WebCoreSources.bkl: Ditto.
        * html/HTMLMediaElement.cpp: Changed to use ContentType.
        (WebCore::HTMLMediaElement::selectMediaURL):
        * platform/ContentType.cpp: Added.
        (WebCore::ContentType::ContentType):
        (WebCore::ContentType::parameter):
        (WebCore::ContentType::type):
        * platform/ContentType.h: Added.
        (WebCore::ContentType::raw):
        * platform/MIMETypeRegistry.cpp:
        * platform/MIMETypeRegistry.h:
        * platform/graphics/MediaPlayer.cpp:
        (WebCore::MediaPlayer::load):
        * rendering/style/ContentData.h: Renamed ContentType to StyleContentType.
        * rendering/style/RenderStyleConstants.h: Ditto.
        (WebCore::):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@41113 268f45cc-cd09-0410-ab3c-d52691b4dbfc