Fixed <rdar://problem/3926825> Safari ignores GIF loop count

	Fixed <rdar://problem/3926825> Safari ignores GIF loop count

	Get loop count from file properties, not image properties.

        Reviewed by Ken Kocienda.

        * WebCoreSupport.subproj/WebImageData.h:
        * WebCoreSupport.subproj/WebImageData.m:
        (-[WebImageData _commonTermination]):
        (-[WebImageData fileProperties]):
        (-[WebImageData _floatProperty:type:at:]):
        (-[WebImageData _floatFileProperty:type:]):
        (-[WebImageData _repetitionCount]):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8343 268f45cc-cd09-0410-ab3c-d52691b4dbfc