tdf#130857 qt weld: Delete unused image label object HEADmaster

QLabel objects created for "GtkImage" objects in .ui file
that are used to set button images are not displayed by themselves,
so unconditionally mark them for deletion once the image data has
been taken over to the button.
(See also use of `aImagesToBeRemoved` in the VclBuilder
ctor for how images used for button images are deleted there.)

This is also no problem if the image is used for multiple
buttons inside of the dialog because QtBuilder::deleteObject
calls QObject::deleteLater, i.e. doesn't delete the object
immediately, but schedules it for deletion once control
returns to the event loop, so reusing it is still safe
until then.

Deleting the QLabel object only if it has no parent isn't
sufficient, because even labels created for "GtkImage"
objects that are top-levels within the corresponding
dialog (or other .ui file)  still have the dialog's parent
widget set as the parent.

Without this commit, a copy paste icon would be shown
on the left hand side of the Writer window after opening and
closing the "Help" -> "About LibreOffice" dialog (which has a
button that has such an icon set.

Change-Id: I40aaaa1af700b4ab0adfdc7a1c04103dfcab7c52
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/180469
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

0 files changed, 0 insertions, 0 deletions