Reviewed by Darin Adler.

        Add tests for ValidityState.stepMismatch.
        https://bugs.webkit.org/show_bug.cgi?id=31331

        * fast/forms/ValidityState-stepMismatch-number-expected.txt: Added.
        * fast/forms/ValidityState-stepMismatch-number.html: Added.
        * fast/forms/ValidityState-stepMismatch-range-expected.txt: Added.
        * fast/forms/ValidityState-stepMismatch-range.html: Added.
        * fast/forms/ValidityState-stepMismatch-unsupported-expected.txt: Added.
        * fast/forms/ValidityState-stepMismatch-unsupported.html: Added.
        * fast/forms/input-step-expected.txt: Added.
        * fast/forms/input-step.html: Added.
        * fast/forms/script-tests/ValidityState-stepMismatch-number.js: Added.
        * fast/forms/script-tests/ValidityState-stepMismatch-range.js: Added.
        * fast/forms/script-tests/ValidityState-stepMismatch-unsupported.js: Added.
        * fast/forms/script-tests/input-step.js: Added.
2009-11-18  Kent Tamura  <tkent@chromium.org>

        Reviewed by Darin Adler.

        Support for step attribute and ValidityStae.stepMismatch for
        type=number and range.  stepMismatch will be false if the
        difference between the current value and a multiple of the step
        value is very small.

        Change the behavior of RenderSlider so that it always has a value
        rounded to the step attribute value.

        https://bugs.webkit.org/show_bug.cgi?id=31331

        Tests: fast/forms/ValidityState-stepMismatch-number.html
               fast/forms/ValidityState-stepMismatch-range.html
               fast/forms/ValidityState-stepMismatch-unsupported.html
               fast/forms/input-step.html

        * html/HTMLAttributeNames.in: Add "step".
        * html/HTMLInputElement.cpp:
        (WebCore::HTMLInputElement::stepMismatch):
        (WebCore::HTMLInputElement::getStepParameters):
        (WebCore::HTMLInputElement::getAllowedValueStep):
        * html/HTMLInputElement.h:
        * html/HTMLInputElement.idl: Add "step".
        * html/ValidityState.cpp:
        (WebCore::ValidityState::stepMismatch): Forward to HTMLInputElement::stepMismatch().
        * html/ValidityState.h:
        * rendering/RenderSlider.cpp:
        (WebCore::SliderRange::SliderRange):
        (WebCore::SliderRange::clampValue):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@51159 268f45cc-cd09-0410-ab3c-d52691b4dbfc