We create the redirected XComposite window unconditionally, but with a size of 1x1 to save memory. However, we are always resizing it, so in the end we always end up with a XWindow allocated for the same size of the web view, even for web views that never enter in AC mode.
Created attachment 244438 [details]
Before this patch a MiniBrowser opened with the default size and URL required 11.2MB, and with the patch it requires 9.5MB.
Thanks for the patch. If this patch contains new public API please make sure it follows the guidelines for new WebKit2 GTK+ API. See http://trac.webkit.org/wiki/WebKitGTK/AddingNewWebKit2API
Committed r178414: <http://trac.webkit.org/changeset/178414>