journal: Support per-framebuffer journals

Instead of having a single journal per context, we now have a
CoglJournal object for each CoglFramebuffer. This means we now don't
have to flush the journal when switching/pushing/popping between
different framebuffers so for example a Clutter scene that involves some
ClutterEffect actors that transiently redirect to an FBO can still be
batched.

This also allows us to track state in the journal that relates to the
current frame of its associated framebuffer which we'll need for our
optimization for using the CPU to handle reading a single pixel back
from a framebuffer when we know the whole scene is currently comprised
of simple rectangles in a journal.

cogl/cogl-texture-private.h

@@ -135,6 +135,7 @@ struct _CoglTextureVtable
 struct _CoglTexture
 {
   CoglHandleObject         _parent;
+  GList                   *framebuffers;
   const CoglTextureVtable *vtable;
 };
 
@@ -165,6 +166,10 @@ struct _CoglTexturePixel
   guint8 data[4];
 };
 
+void
+_cogl_texture_init (CoglTexture *texture,
+                    const CoglTextureVtable *vtable);
+
 void
 _cogl_texture_free (CoglTexture *texture);
 
@@ -285,4 +290,14 @@ _cogl_texture_set_region_from_bitmap (CoglHandle    handle,
                                       unsigned int  dst_height,
                                       CoglBitmap   *bmp);
 
+void
+_cogl_texture_associate_framebuffer (CoglHandle handle,
+                                     CoglFramebuffer *framebuffer);
+
+const GList *
+_cogl_texture_get_associated_framebuffers (CoglHandle handle);
+
+void
+_cogl_texture_flush_journal_rendering (CoglHandle handle);
+
 #endif /* __COGL_TEXTURE_PRIVATE_H */