make bounds roundOut in raster_cache.

Runtime/flow/raster_cache.cs

         public readonly float devicePixelRatio;
 
         public void draw(Canvas canvas) {
-            var bounds = canvas.getTotalMatrix().mapRect(this.logicalRect);
+            var bounds = canvas.getTotalMatrix().mapRect(this.logicalRect).roundOut();
 
             D.assert(() => {
                 var textureWidth = Mathf.CeilToInt(bounds.width * this.devicePixelRatio);
 
         RasterCacheResult _rasterizePicture(Picture picture, Matrix3 transform, float devicePixelRatio,
             MeshPool meshPool) {
-            var bounds = transform.mapRect(picture.paintBounds);
+            var bounds = transform.mapRect(picture.paintBounds).roundOut();
 
             var desc = new RenderTextureDescriptor(
                 Mathf.CeilToInt((bounds.width * devicePixelRatio)),