Fix the decoration is not included, when isWrapRequired is called.

[forceson]

Problem & How to solve

When the screen which is using FlexboxLayoutManager is rendered, FlexboxHelper#isWrapRequired is called. In that case, we are using RecyclerView, so the decoration length must be calculated, but it is not calculated in FlexboxHelper#isWrapRequired. So, I added calculateItemDecorationsForChild when FlexContainer has to calculate the decoration.

I know that calculateItemDecorationsForChild does not to be called in FlexLayout, but FlexLayout and FlexLayoutManager is abstracted with FlexContainer, so I could not find the way how distribute calculateItemDecorationsForChild function.

Welcome any comments.

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[forceson]

@googlebot I signed it!

[thagikura]

Hi @forceson thanks for your pull request and apologies for the delayed reply.

Indeed it should be resolved that the decoration length is not taken into account for FlexboxLayoutManager. Is it possible to add some test cases that fail unless this pull request is applied?