QWindowsScreen uses setupAPI.h's SetupDiOpenDevRegKey function to read
EDID data for monitors. This function is documented as returning
INVALID_HANDLE_VALUE in case of failure.
The QWindowsScreen code was ambiguous in the sense that it considered
both nullptr and INVALID_HANDLE_VALUE as being invalid handle values.
This inconsistency is likely not a bug, but makes the code harder to
understand.
This patch removes this ambiguity, and QWindowsScreen now follows the
documented behavior when SetupDiOpenDevRegKey fails. In addition, we
replace use of unique_ptr with the new QUniqueHandle template class
because HKEY is a handle type, not a regular pointer type.
Pick-to: 6.5 6.6
Change-Id: Ia863bda504077e59833f6f7a0f855e7915e4edd9
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
55141c59cd