Before this patch, any time TreeItem is copied in Resize method, its
parent is not updated, which can cause crashes when, for example, thread
window with multiple hierarchy levels is updated. Makes TreeItem
move-only, removes TreeItem's m_delegate extra self-assignment by making
it a pointer, adds code to fix up children's parent on move constructor
and operator=
Patch prepared by NH5pml30
~~~
Huawei RRI, OS Lab
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D157960
83695d45d6