Summary:
The method is supposed to return the AbstractClient's size for a given
client size. That is the size including the window decoration.
The default implementation returned the passed in client size without
adjusting for the decoration. This resulted in ShellClient getting a
wrong size especially when AbstractClient::adjustedClientSize (which
calls sizeForClientSize) was called.
The result of the incorrect size was for example a shrinking of the
window when starting to resize a window.
BUG: 370345
FIXED-IN: 5.8.4
Reviewers: #kwin, #plasma_on_wayland, broulik, subdiff
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3414
Martin Gräßlin