NoBorder.fxg

<Graphic version="2.0" xmlns="http://ns.adobe.com/fxg/2008"
    scaleGridLeft="0" scaleGridTop="0" scaleGridRight="0" scaleGridBottom="0">
    
    <Rect x="0" y="0" width="1" height="1">
        <fill>
            <SolidColor color="#FFFFFF" alpha="0" />
        </fill>
    </Rect>
</Graphic>

SplitViewActionBarSkin.as

package meridiantablet.skins
{
	import flash.display.GradientType;
	import flash.display.Graphics;
	import flash.geom.Matrix;
	
	import spark.skins.mobile.ActionBarSkin;
	
	public class SplitViewActionBarSkin extends ActionBarSkin
	{
		public function SplitViewActionBarSkin()
		{
			super();
			
			borderClass = NoBorder;
		}
		
		override protected function drawBackground( unscaledWidth:Number, unscaledHeight:Number ):void
		{
			var g:Graphics = graphics;
			g.clear();
			
			g.beginFill( 0x000000, 1 );
			g.drawRect( 0, 0, unscaledWidth, unscaledHeight );
			g.endFill();
			
			var m:Matrix = new Matrix();
			m.createGradientBox( unscaledWidth, unscaledHeight, Math.PI / 2 );
			
			g.beginGradientFill( GradientType.LINEAR, [ 0xFEFEFE, 0xDADDE2, 0xA6AAB7 ], [ 1, 1, 1 ], [ 0, 127, 240 ], m );
			g.drawRoundRectComplex( 0, 0, 320, unscaledHeight, 5, 5, 0, 0 );
			g.endFill();
			
			g.beginGradientFill( GradientType.LINEAR, [ 0xFEFEFE, 0xDADDE2, 0xA6AAB7 ], [ 1, 1, 1 ], [ 0, 127, 240 ], m );
			g.drawRoundRectComplex( 321, 0, unscaledWidth - 321, unscaledHeight, 5, 5, 0, 0 );
			g.endFill();
		}
	}
}