On UWP D3D project UI input field throws exceptions, touchscreen keyboard doesn't open.

Reproducible on 5.3

Repro steps:
1. open "uiInput.zip".
2. build to UWP platform D3D type.
3. launch on Windows Phone or Windows tablet and select UI input field.

Exception:
Unhandled 'Platform.WrongThreadException' exception caught! - 'The application called an interface that was marshalled for a different thread.
The application called an interface that was marshalled for a different thread.
', Sender: '<null>'. Missing try/catch blocks.
(Filename: C:\buildslave\unity\build\PlatformDependent/MetroPlayer/MetroDebug.cpp Line: 38)

Reproducible on 5.3.2.
On 5.4.0 beta versions exception is not showed in the console.

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By design:
D3D build type doesn't support touchscreen keyboard, that's why input fields throw exceptions.