https://bugs.webkit.org/show_bug.cgi?id=74229
<rdar://problem/10558627>

Reviewed by Darin Adler.
Patch by Simon Fraser.

For animation property wrappers around StyleImage properties,
test the equivalence of the image itself, instead of equality of
the StyleImage pointer.

Test: transitions/equivalent-background-image-no-transition.html

* page/animation/AnimationBase.cpp:
(WebCore::StyleImagePropertyWrapper::StyleImagePropertyWrapper):
(WebCore::StyleImagePropertyWrapper::equals):
(WebCore::FillLayerStyleImagePropertyWrapper::FillLayerStyleImagePropertyWrapper):
(WebCore::FillLayerStyleImagePropertyWrapper::equals):
(WebCore::FillLayersPropertyWrapper::FillLayersPropertyWrapper):
(WebCore::AnimationBase::ensurePropertyMap):

Add a test ensuring that background-images aren't needlessly transitioned
when they are equivalent.

* transitions/equivalent-background-image-no-transition-expected.txt: Added.
* transitions/equivalent-background-image-no-transition.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@102498 268f45cc-cd09-0410-ab3c-d52691b4dbfc