No LayoutTransformControl in WinUI

[ejserna]

Describe the bug
For #3492, we need a LayoutTransformControl, which WinUI doesn't have (yet).

Steps to reproduce the bug

Steps to reproduce the behavior:

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2. Click on '....'

Expected behavior

Screenshots

Version Info

NuGet package version:

Windows app type:

UWP	Win32

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
May 2020 Update (19041)
November 2019 Update (18363)
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop
Xbox
Surface Hub
IoT

Additional context

[mdtauk]

The Windows Community Toolkit has one
https://docs.microsoft.com/en-us/windows/communitytoolkit/controls/layouttransformcontrol

[ranjeshj]

WPF supports LayoutTransform in the framework so this is a gap. Unfortunately render transform does not update the layout bounds of the element.

[mdtauk]

WPF supports LayoutTransform in the framework so this is a gap. Unfortunately render transform does not update the layout bounds of the element.

The need for it in WinUI is to enable the new Expander control to be able to expand to the Left or Right.

In time, this may also allow for Vertical Tabs which can be rotated and placed to the left or right.

[robloo]

LayoutTransform really needs to be in the framework itself like RenderTransform. What was done in the WCT to create a separate control is only a work-around.

[michael-hawker]

🦙 @chrisglein FYI, this is a duplicate of #546. I had added it early on specifically because of Expander and it's usefulness in other scenarios for the WPF gap.

[chrisglein]

Duplicate of #546