The gyp files already define NOMINMAX and WIN32_LEAN_AND_MEAN.  windows.h
is also included via the D3D includes.

This ends up speeding up the build process significantly by not having
windows.h included in nearly every file.

Also fixes issues on non-windows systems by not having stdarg.h included
in debug.cpp.

Change-Id: Id32d9aac37a5a29df832a062dd8024302a798a1c
Reviewed-on: https://chromium-review.googlesource.com/182810Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>