How to force canvas drawn views to be in an exact dimension?

Question

I'm trying to force a drawn view to be in an exact dimension. No matter how I try it ignores the dimensions.

Code:

My view to be drawn in 250x250 pixels:

public class MyCustomView extends View {
    public MyCustomView(Context context) {
        super(context);
    }

    public MyCustomView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        FlowLayout layout = new FlowLayout(getContext());

        for (int i = 0; i < 30; i++) {
            TextView textView = new TextView(getContext());
            textView.setText("[text#" + i + "]");
            textView.setBackgroundColor(Color.GREEN);
            layout.addView(textView);
        }

        int dimension = 250;

        layout.measure(
                dimension,
                dimension);

        layout.layout(0, 0,
                dimension,
                dimension);

        layout.draw(canvas);

    }
}

Result:

The layout clearly not renders in 250x250 pixels.

If I swap the FlowLayout to a standard Android SDK layout, like to a Linear Layout, the result is the same.

Please help if you can.