Reviewed by Oliver.

        Fix for <rdar://problem/5586370> CSS Transform - incorrect matrix 
        math leads to crazy problems

        Transform matrices accept the first four parameters as CSS lengths. 
        CSS lengths get mapped into WebCore::Lengths as percents by 
        WebCore::convertToLength(). Percent lengths cannot call value(). It 
        does not yield a correct result and it asserts on Debug builds. 

        * rendering/RenderStyle.h:
        (WebCore::MatrixTransformOperation::apply): Instead of calling 
        value() on the lengths, call calcValue. This fixes the assert and 
        the bad rendering. 

LayoutTests:

        Reviewed by Oliver.

        Test for <rdar://problem/5586370> CSS Transform - incorrect matrix 
        math leads to crazy problems

        * fast/transforms/identity-matrix.html: Added.
        * platform/mac/fast/transforms/identity-matrix-expected.checksum: Added.
        * platform/mac/fast/transforms/identity-matrix-expected.png: Added.
        * platform/mac/fast/transforms/identity-matrix-expected.txt: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@27649 268f45cc-cd09-0410-ab3c-d52691b4dbfc