Background

The FlutterWindow is one of the fundamental types of the Windows embedder. It listens to the Windows event loop, processes keyboard events, handles IME composition, accessibility, and more.

On top of all of this, it is also used to mock win32 APIs:

• Get DWM composition status ([Windows] Move DWM composition status to Windows proc table for mocking engine#49397)
• Flush DWM ([Windows] Move DWM flush to Windows proc table for mocking engine#49398)
• Peek and send win32 messages
• Map virtual key
• Default window procedure

These are debatable candidates:

• Clear and present bitmaps

Solution

The WindowsProcTable was introduced to allow mocking win32 APIs. FlutterWindow methods that exist for mocking purposes should be moved to the WindowsProcTable.