Remove duplicate code in RenderBoxModelObject::computedCSSPadding*
https://bugs.webkit.org/show_bug.cgi?id=108707

Reviewed by Levi Weintraub.

The computedCSSPaddingTop/Bottom/... methods in
RenderBoxModelObject all do pretty much exactly the same thing
yet share no code.

Break out shared code into computedCSSPadding method and have
the top/bottom/left/right/... ones call it with the appropriate
length value.

No new tests, no change in functionality.

* rendering/RenderBoxModelObject.cpp:
(WebCore::RenderBoxModelObject::computedCSSPadding):
* rendering/RenderBoxModelObject.h:
(WebCore::RenderBoxModelObject::computedCSSPaddingTop):
(WebCore::RenderBoxModelObject::computedCSSPaddingBottom):
(WebCore::RenderBoxModelObject::computedCSSPaddingLeft):
(WebCore::RenderBoxModelObject::computedCSSPaddingRight):
(WebCore::RenderBoxModelObject::computedCSSPaddingBefore):
(WebCore::RenderBoxModelObject::computedCSSPaddingAfter):
(WebCore::RenderBoxModelObject::computedCSSPaddingStart):
(WebCore::RenderBoxModelObject::computedCSSPaddingEnd):
(RenderBoxModelObject):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141669 268f45cc-cd09-0410-ab3c-d52691b4dbfc