Gird - formatter widget doesn't get destroyed which leads to significant leaks

[Evan]

This happens to all grid types including DataGrid?, EDG, TreeGrid? and LazyTreeGrid? - when formatter() is used to return widgets, all the widgets are not cleaned up when user keep scrolling or creating/destroying a grid instance, and this results into significant memory increase like 50M in a very shot time e.g. 10-15mins, this can be observed in the attached test case.

[Evan]

Test case to reproduce the leaks when keep scrolling a grid instance

[Evan]

snapshot of the leaks

[Evan]

In [26619]:

Fixes #13961 !strict

1. widget._destroyOnRemove should be used to ensure the widget get destroyed when a page is removed, e.g. function formatter(){

var w = new dijit.form.TextBox?({...});
w._destroyOnRemove = true;
return w;

}

2. _View.js Ensure the widget nodes are not orphaned when a row/page is destroyed

3. _Grid.js Ensure the correct sequence within Grid.destroy() so that widget nodes are not orphaned.

Thanks for the patch from Elvis(IBM, CCLA)/Oliver(IBM, CCLA)!

[Evan]

In [26621]:

Refs #13961 !strict, remove obsolete spaces and ensure expandos get removed in LazyTreeGrid?.destroy()

[Evan]

In [26625]:

Refs #13961 !strict, fix a regression, widget dom node shouldn't be removed without '_destroyOnRemove = true'

[Evan]

In [26673]:

Refs #13961 !strict, backport fix of #13961 to 1.6 branch