The logic for invalidating a theme QIcon when the platform theme
changed, or when the user set an explicit icon theme, was tied
to QIconLoaderEngine, so any platform theme implementing
QPlatformTheme::createIconEngine() with a custom icon engine
would not take part in this cache invalidation.
As we want users of QIcon::fromTheme to be agnostic to where the
icon is actually coming from, and have a consistent behavior for
the various QIcon APIs for setting explicit themes, the logic
for invalidating the themed icon has now been moved up one
layer, to a new QThemeIconEngine, that is responsible for
lazily creating the actual engine based on the name. The
engine proxies the actual icon loading through to the
real engine via a new QProxyIconEngine helper class.
Pick-to: 6.6
Change-Id: I474589981f751d7467e3073533cba542182f2d36
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>
a452e22546