Allow opaque windows to become translucent.

        if (fullscreen == toOpaque) {

            return false;

        }

        AttributeCache.Entry ent =

                AttributeCache.instance().get(packageName, realTheme, styleable.Window, userId);

        if (ent == null

                || !ent.array.getBoolean(styleable.Window_windowIsTranslucent, false)

                || ent.array.getBoolean(styleable.Window_windowIsFloating, false)) {

            return false;

        }

        // Keep track of the number of fullscreen activities in this task.

        task.numFullscreen += toOpaque ? +1 : -1;