Source/WebCore: Implement reverse animation direction

Source/WebCore: Implement reverse animation direction

Implement reverse animation direction
https://bugs.webkit.org/show_bug.cgi?id=60525

Implement reverse and alternate-reverse direction.

Reviewed by Dean Jackson.

Tests: animations/animation-direction-alternate-reverse.html
       animations/animation-direction-reverse.html
       animations/fill-mode-reverse.html

* css/CSSParser.cpp:
(WebCore::CSSParser::parseAnimationDirection):
* css/CSSStyleSelector.cpp:
(WebCore::CSSStyleSelector::mapAnimationDirection):
* css/CSSValueKeywords.in:
* page/WebKitAnimation.cpp:
(WebCore::WebKitAnimation::direction):
* page/WebKitAnimation.h:
* page/animation/AnimationBase.cpp:
(WebCore::AnimationBase::fractionalTime):
* platform/animation/Animation.h:
(Animation):
* platform/graphics/texmap/TextureMapperAnimation.cpp:
(WebCore):
(WebCore::shouldReverseAnimationValue):
(WebCore::normalizedAnimationValue):

LayoutTests: Implement reverse animation direction
https://bugs.webkit.org/show_bug.cgi?id=60525

Add test for the new animation-direction values.

Reviewed by Dean Jackson.

* animations/animation-direction-alternate-reverse-expected.txt: Added.
* animations/animation-direction-alternate-reverse.html: Added.
* animations/animation-direction-reverse-expected.txt: Added.
* animations/animation-direction-reverse.html: Added.
* animations/fill-mode-reverse-expected.txt: Added.
* animations/fill-mode-reverse.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@107162 268f45cc-cd09-0410-ab3c-d52691b4dbfc