Added IInspectable EGLNativeWindowType and ICoreWindow support

Change-Id: I9ad82b7819bcca1c05e7aa60dc2baec4a7bc403c
Reviewed-on: https://chromium-review.googlesource.com/222360
Tested-by: Cooper Partin <coopp@microsoft.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>