Avoid extraneous EGL surface allocations

Bug #8667873

windowShouldResize means we need to layout the window, it doesn't mean
the dimensions of the surface have changed. We should only check the
width and the height. With this fix we can avoid a surface allocation
every time the window shade is opened or closed.

Change-Id: I8afe97b820a865723f2aab7a5aa4ddc8eaaec6e1