From @keyframes rules with the same name, the last rule should be used

https://bugs.webkit.org/show_bug.cgi?id=73113

Source/WebCore:

Have later rules override previously stored rules.

Reviewed by Simon Fraser.

Test: animations/duplicated-keyframes-name.html

* css/CSSStyleSelector.cpp:
(WebCore::CSSStyleSelector::addKeyframeStyle):

LayoutTests:

Verify that the last @keyframe rule is used.

Reviewed by Simon Fraser.

* animations/duplicated-keyframes-name-expected.txt: Added.
* animations/duplicated-keyframes-name.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@101321 268f45cc-cd09-0410-ab3c-d52691b4dbfc