Add column width recalculation when vertical scrollbar hidden/shown.

[Ansku]

• If the Grid has any columns with non-fixed widths, the presence of a
  vertical scrollbar affects the column width calculations. Horizontal
  scrollbar should only be shown when actually needed.

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This change is 

[edler-san]

Reviewed 6 of 6 files at r1.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @Ansku)

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uitest/src/main/java/com/vaadin/tests/components/grid/GridSizeChange.java, line 29 at r1 (raw file):

        grid = new Grid<>();
        data = new ArrayList<>();
        for (int i = 0; i < 8; ++i) {

Any reason for the change of data elements?
(Maybe introduce constant for them.)

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uitest/src/main/java/com/vaadin/tests/components/grid/GridSizeChange.java, line 43 at r1 (raw file):

        grid.setHeightByRows(8);
        grid.setWidth(100, Unit.PIXELS);

Same as above

[Ansku]

Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @edler-san)

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uitest/src/main/java/com/vaadin/tests/components/grid/GridSizeChange.java, line 29 at r1 (raw file):

Previously, edler-san wrote…

Any reason for the change of data elements?
(Maybe introduce constant for them.)

You mean why it's 8 now when it used to be 10? That's because now it tests the scrollbar response for both scrollbars instead of just one at a time, and the tweaks are to ensure all the items within the test have the same number of digits so that we don't get a horizontal scrollbar just because row_10 takes more room than row_9 (relevant for the bit when 'Add row' is clicked). There was no particular reason to select 10 to start with, it's just an easy number to come up with.

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uitest/src/main/java/com/vaadin/tests/components/grid/GridSizeChange.java, line 43 at r1 (raw file):

Previously, edler-san wrote…

        grid.setHeightByRows(8);
        grid.setWidth(100, Unit.PIXELS);

Same as above

Likewise, the initial width was selected so that it worked to test the initial setting where the column width calculations were still broken. Now that they work, it turned out that 90 pixels was just a bit too narrow for one of the new tests to work properly to test what they are supposed to test for both scrollbars at the same time. The old tests are still there and work either way.

[edler-san]

Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @edler-san)