Generate toCSSFooValue() for CSSCursorImageValue, CSSCubicBezierTimingFunctionValue, CSSStepsTimingFunctionValue and CSSUnicodeRangeValue
https://bugs.webkit.org/show_bug.cgi?id=122408

Reviewed by Andreas Kling.

As a step to use toCSSFooValue, this patch generates toCSSFooValue() for CSSCursorImageValue,
CSSCubicBezierTimingFunctionValue, CSSStepsTimingFunctionValue and CSSUnicodeRangeValue.
This will help to detect bad type cast.

No new tests, no behavior changes.

* css/CSSCursorImageValue.h:
* css/CSSTimingFunctionValue.h:
* css/CSSToStyleMap.cpp:
(WebCore::CSSToStyleMap::mapAnimationTimingFunction):
* css/CSSUnicodeRangeValue.h:
* css/CSSValue.cpp:
(WebCore::CSSValue::destroy):
* css/DeprecatedStyleBuilder.cpp:
(WebCore::ApplyPropertyCursor::applyValue):
* css/StyleResolver.cpp:
(WebCore::StyleResolver::styleImage):
(WebCore::StyleResolver::styleShader):
* rendering/style/StylePendingImage.h:
(WebCore::StylePendingImage::cssCursorImageValue):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@157024 268f45cc-cd09-0410-ab3c-d52691b4dbfc