[Performance] Layout node slots only on resize

[huchenlei]

Perform slot layout only when node is resized.

[huchenlei]

Recommend leaving this unless it's a perf bottleneck - it should only provied a tiny benefit. If it's larger, it'd probably be faster to fix that instead. Making this work across the board with e.g. size[0] += 10 would require some special handling.

Test is failure because the frontend domWidgets.computeSize is getting it's own size adjustment into the loop without properly trigger the resize. (Probably avoid infinite loop of onResize?).

Need to do that cleanup before we can do the move of slot layout.

[webfiltered]

Recommend leaving this unless it's a perf bottleneck - it should only provied a tiny benefit. If it's larger, it'd probably be faster to fix that instead. Making this work across the board with e.g. size[0] += 10 would require some special handling.

[huchenlei]

Recommend leaving this unless it's a perf bottleneck - it should only provied a tiny benefit. If it's larger, it'd probably be faster to fix that instead. Making this work across the board with e.g. size[0] += 10 would require some special handling.

I moved the check to monitor boundingRect change, which should detect all size change, and trigger re-layout only when size of node has changed.