ContentTypeUtilities.cpp has been added in r294634, but it can break some unified builds because of such errors:

In file included from WebCore/DerivedSources/unified-sources/UnifiedSource-3c72abbe-22.cpp:2:
In file included from ../../Source/WebCore/platform/graphics/CrossfadeGeneratedImage.cpp:27:
In file included from ../../Source/WebCore/platform/graphics/CrossfadeGeneratedImage.h:28:
In file included from ../../Source/WebCore/platform/graphics/FloatSize.h:30:
In file included from ../../Source/WebCore/platform/graphics/IntPoint.h:28:
../../Source/WebCore/platform/graphics/IntSize.h:212:16: error: no type named 'TextStream' in namespace 'WebCore::WTF'; did you mean simply 'TextStream'?
WEBCORE_EXPORT WTF::TextStream& operator<<(WTF::TextStream&, const IntSize&);
               ^~~~~~~~~~~~~~~
               TextStream
WTF/Headers/wtf/Forward.h:160:12: note: 'TextStream' declared here
using WTF::TextStream;
           ^

This is because it can make <wtf/Forward.h> included from the WebCore namespace.