Major changes to nsComboboxControlFrame:
Removed commented out code + nsIPluggableEventListener references.
Implemented nsComboboxControlFrame::GetNamesValues
Implemented nsComboboxControlFrame::SetProperty GetProperty methods
Fixed references to previously freed memory in nsComboboxControlFrame::ReResolveStyleContext
Modified ua.css style rules for dropdown-visible, drodown-hidden to have -moz- prefix.
Added -moz-dropdown-btn-out and -moz-dropdown-btn-pressed, -moz-dropdown-list rules.
Modified nsListControlFrame.cpp to calculate the width of the dropdown list for combo boxes correctly
Added nsListControlFrame::GetProperty and SetProperty methods.
Modified nsCSSFrameConstructor::ConstructSelectFrame to setup combobox.
Added methods to GetWidgetRenderingMode and SetWidgetRenderingMode in nsPresContext
Removed NS_GFX_RENDER_FORM_ELEMENTS define, now it uses the GetWidgetRenderingMode
method on the rendering context.
Resurrected Rod's listbox frame-based widget code.
Added -moz-option-selected pseudo attribute to control the appearance of selected items for the listbox frame-based widget.
Added a style rule with attribute selector for -moz-option-selected to the ua.css style sheet.
Modifed nsView::SetVFlags to do a bitwise or instead of bitwise and to set flags.
Modified nsView::HandleEvent to compare mVFlags with NS_VIEW_FLAG_DONT_CHECK_CHILDREN
