clutter-stage: Set the Cogl framebuffer size after allocating
clutter-stage: Set the Cogl framebuffer size after allocating

When handling an allocation on the stage, Clutter uses the oppurtunity
to inform Cogl of the new size of the framebuffer so that it can
handle the viewport correctly. It queries the size of the window
implementation using a backend virtual function. However it was doing
this before letting the backend handle the allocation so on Win32 it
would end up using the previous framebuffer size. This wasn't
affecting the X11 backend because in that case the resizes are
asynchronous so setting the stage size causes one allocation which
ends up sending a window size request. Eventually a ConfigureNotify is
received which causes the size of the stage to be set again and
another allocation is fired meaning the framebuffer size will be set
again this time with the correct size. In Win32 the resizes are
synchronous so we don't have this second allocation.

ebassi/clutter,djdeath/clutter,heysion/clutter-clone,heysion/clutter-clone,Distrotech/clutter,djdeath/clutter-android,jigpu/clutter,GNOME/clutter,spatulasnout/clutter,djdeath/clutter,ebassi/clutter,collects/clutter,jigpu/clutter,kerrickstaley/clutter-vala,djdeath/clutter,djdeath/clutter-android,djdeath/clutter-multithreaded,GNOME/clutter,spatulasnout/clutter,nobled/clutter,collects/clutter,jigpu/clutter,spatulasnout/clutter,spatulasnout/clutter,Distrotech/clutter,Distrotech/clutter,GNOME/clutter,dlespiau/clutter,djdeath/clutter,kerrickstaley/clutter-vala,jigpu/clutter,ebassi/clutter,GNOME/clutter,djdeath/clutter-android,heysion/clutter-clone,GNOME/clutter,Distrotech/clutter,collects/clutter,heysion/clutter-clone,ebassi/clutter,djdeath/clutter-android,collects/clutter,nobled/clutter,Distrotech/clutter,spatulasnout/clutter,djdeath/clutter-multithreaded,nobled/clutter,djdeath/clutter-multithreaded,kerrickstaley/clutter-vala,ebassi/clutter,djdeath/clutter-android,dlespiau/clutter,heysion/clutter-clone,Distrotech/clutter,collects/clutter,kerrickstaley/clutter-vala,dlespiau/clutter,djdeath/clutter-multithreaded,jigpu/clutter,jigpu/clutter,djdeath/clutter,djdeath/clutter