Add calendar header for new calendar picker
https://bugs.webkit.org/show_bug.cgi?id=110967

Reviewed by Kent Tamura.

The calendar header showing the current month and containing navigation
buttons, which will be part of the new calendar picker (Bug 109439).

No new tests. Code is not yet used.

* Resources/pagepopups/calendarPicker.js:
(MonthPopupButton): Button that opens the month popup.
(MonthPopupButton.prototype._shouldUseShortMonth): Returns true if we should use the short month format in order to fit in the available width.
(MonthPopupButton.prototype.setCurrentMonth): Sets the month to the button label.
(MonthPopupButton.prototype.onClick): Dispatches buttonClick event which will tell the calendar picker to open the month popup.
(CalendarNavigationButton): A square button that fires repeatedly while the mouse is pressed down.
(CalendarNavigationButton.prototype.setDisabled):
(CalendarNavigationButton.prototype.onClick):
(CalendarNavigationButton.prototype.onMouseDown): Sets the timer to fire while the mouse is pressed down.
(CalendarNavigationButton.prototype.onWindowMouseUp):
(CalendarNavigationButton.prototype.onRepeatingClick):
(CalendarHeaderView): View containing month popup button and the navigation buttons.
(CalendarHeaderView.prototype.onCurrentMonthChanged): Sets the MonthPopupButton label and checks if the navigation buttons should be disabled.
(CalendarHeaderView.prototype.onNavigationButtonClick):
(CalendarHeaderView.prototype.setDisabled): Used to disable all the buttons while the month popup is open.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144298 268f45cc-cd09-0410-ab3c-d52691b4dbfc