Change elevation to double of MergeableMaterial

[Abhishek01039]

Update elevation from int to double
Fixes #11468

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[flutter-dashboard]

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[Abhishek01039]

Hello @Hixie
can you please review this PR?
Thanks

[Hixie]

test-exempt: code refactor

Please don't forget to update the commit message above.

There's a bunch of places in this file that use "toDouble" that should now be redundant. We should remove those as well. (@a14n: might be worth a lint -- flagging cases where one has used toDouble() on a type we know statically to be a double, and similar, e.g. .round() on an int, or .toString() on a String)

If this lands successfully, we should also consider doing the next one up the chain, ExpansionPanel.

[Abhishek01039]

Thanks @Hixie
I have removed those and updated the commit message

[Hixie]

LGTM, assuming the tests pass! (The Google Testing ones are the ones I'm mostly concerned about...)

[Abhishek01039]

Hey @Hixie
I have seen you in one of the boring flutter show
you are good tutor as well as Engineer
thanks for your hard work because I can see today is your holiday still you are doing work for make flutter better!

[thecalamiity]

Why the .toDouble() for the expansion tile?

[thecalamiity]

Also this probably fixes #11468

[Abhishek01039]

hello @mrbirb
because expansion tile has final int elevation;

[Hixie]

we should file a bug about ExpansionPanelList using int for elevation now too

[Abhishek01039]

Sure @Hixie
And please assign to me!
Thanks

[Hixie]

By "we" I meant "you", really. :-)

[Abhishek01039]

Great