ClutterTexture has many features that we simply don't use and don't make
sense for a subclass with custom drawing. Deriving directly from ClutterActor
simplifies our code by avoiding workarounds and makes things more robust.
Additionally, make it public. GNOME Shell was already assuming that any
MetaShapedTexture was also a ClutterTexture, and we need to replace these
bits with new API for GNOME Shell to use.
https://bugzilla.gnome.org/show_bug.cgi?id=660941
MetaShapedTexture can be a ClutterX11TexturePixmap sub-class, given that
ClutterGLXTexturePixmap is just a shim compatibility layer since Clutter
1.4, and it's been deprecated.
https://bugzilla.gnome.org/show_bug.cgi?id=655064
Move all objects and functions namespaced with Mutter into the Meta namespace
to get a single consistent namespace. Changes that aren't simply changing mutter
to meta:
MutterWindow => MetaWindowActor
mutter_get_windows => meta_get_window_actors
mutter_plugin_get_windows => meta_plugin_get_window_actors
https://bugzilla.gnome.org/show_bug.cgi?id=628520