Bug 97636 – [Forms] Move code fragment for current local time into common place

• Status: NEW
• Component: Forms

There are same code fragment in
 - MonthInputType::defaultValueForStepUp() http://trac.webkit.org/browser/trunk/Source/WebCore/html/MonthInputType.cpp#L88
 - TimeInputType::defaultValueForStepUp() http://trac.webkit.org/browser/trunk/Source/WebCore/html/TimeInputType.cpp#L79
Note: We should have defaultValueForStepUp() for DateTimeLocalInputType and WeekInputType.

We should have function to calculate local current time, currentLocalTimeMs().
    double current = currentTimeMS();
    double utcOffset = calculateUTCOffset();
    double dstOffset = calculateDSTOffset(current, utcOffset);
    int offset = static_cast<int>((utcOffset + dstOffset) / msPerMinute);
    current += offset * msPerMinute;