Windows implementation for FrameBuffer needs priority over Ozone.

When building Chrome for Windows using Ozone, since use_ozone=true,
some required windows definitions don't get defined.

Change-Id: I6b8475c036dc88f7e3cb118a7db286afc75857fe
Reviewed-on: https://swiftshader-review.googlesource.com/17968Tested-by: Mustafa Çamurcu <camurcu@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>