The matrix() returned by getComputedStyle().webkitTransform has the transform origin in it, which is, I think, incorrect. It should be possible to assign the result of getComputedStyle().webkitTransform back to element.style.webkitTransform and not have the element move.
Created attachment 22900 [details] Testcase
Created attachment 22901 [details] Patch, testcase, changelog
Comment on attachment 22901 [details] Patch, testcase, changelog r=me
Committed r35862 M WebCore/rendering/style/RenderStyle.cpp M WebCore/rendering/style/RenderStyle.h M WebCore/ChangeLog M WebCore/css/CSSComputedStyleDeclaration.cpp M LayoutTests/ChangeLog r35862 = be1d24c242df001aa5ff47bc008712a76460dd98 (trunk)