Redesign wlr_texture

- Textures are now immutable (apart from those created from raw
  pixels), no more invalid textures
- Move all wl_drm stuff in wlr_renderer
- Most of wlr_texture fields are now private
- Remove some duplicated DMA-BUF code in the DRM backend
- Add more assertions
- Stride is now always given as bytes rather than pixels
- Drop wl_shm functions

Fun fact: this patch has been written 10,000 meters up in the air.

include/wlr/render/wlr_renderer.h

@@ -1,8 +1,6 @@
 #ifndef WLR_RENDER_WLR_RENDERER_H
 #define WLR_RENDER_WLR_RENDERER_H
 
-#include <EGL/egl.h>
-#include <EGL/eglext.h>
 #include <stdint.h>
 #include <wayland-server-protocol.h>
 #include <wlr/render/wlr_texture.h>
@@ -21,10 +19,6 @@ void wlr_renderer_clear(struct wlr_renderer *r, const float color[static 4]);
  * box.
  */
 void wlr_renderer_scissor(struct wlr_renderer *r, struct wlr_box *box);
-/**
- * Requests a texture handle from this renderer.
- */
-struct wlr_texture *wlr_render_texture_create(struct wlr_renderer *r);
 /**
  * Renders the requested texture.
  */
@@ -51,10 +45,15 @@ void wlr_render_colored_ellipse(struct wlr_renderer *r,
 const enum wl_shm_format *wlr_renderer_get_formats(struct wlr_renderer *r,
 	size_t *len);
 /**
- * Returns true if this wl_buffer is a DRM buffer.
+ * Returns true if this wl_buffer is a wl_drm buffer.
  */
-bool wlr_renderer_buffer_is_drm(struct wlr_renderer *renderer,
+bool wlr_renderer_resource_is_wl_drm_buffer(struct wlr_renderer *renderer,
 	struct wl_resource *buffer);
+/**
+ * Gets the width and height of a wl_drm buffer.
+ */
+void wlr_renderer_wl_drm_buffer_get_size(struct wlr_renderer *renderer,
+	struct wl_resource *buffer, int *width, int *height);
 /**
  * Reads out of pixels of the currently bound surface into data. `stride` is in
  * bytes.