[evita] ui: Revise lazy canvas painting assertions.
[evita] ui/controls: Re-implement |ui::TableControl| for lazy canvas painting.
[evita] gfx:: Introduce |gfx::Canvas::should_clear()| and utilize it.
[evita] ui/controls: Use |ui::Widget::OnDraw(gfx::Canvas*)| rather than |ui::ScrollBar::Render(gfx::Canvas*)| to paint scroll for using scroll bar in table window.
[evita] gfx: Add dirty rectangle automatically when we need to clear |gfx::Canvas| for getting rid of Clear+AddDirtyRect pattern.
[evita] views: Utilize lazy canvas creation in |views::MessageView| to simplify implementation.
[evita] views: Utilize |ui::AnimationFloat| in |views::MessageView|.