Fix XDG application shrinks

WM set surface source size output_size(1080X1920) in case of using runXDG.
Then, XDG surface shrinks because dest size(1080X1488) is set and
the surface is scaled.

On the other hand, XDG application's source size is w = 0, h = 0
on startup from ivi-wm, so WM has to set source size in somewhere.
So this patch fixes WM set XDG surface source size.

This is short term solution because WM set source rectangle size
every state changes.

Bug-AGL: SPEC-1584

Change-Id: I128db0b7feaba6b51e13c467e91d5aff6adaf0a7
Signed-off-by: Kazumasa Mitsunari <knimitz@witz-inc.co.jp>