Remove unused uniscribe header

The uniscribe code is no longer used for fallback fonts.
Remove the unused include file.

R=drott@chromium.org

Change-Id: Ib40a1f6fb989c9de237861ee61ef96d2c3b5c70a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808264
Commit-Queue: Dominik Röttsches <drott@chromium.org>
Reviewed-by: Dominik Röttsches <drott@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697930}

third_party/blink/renderer/platform/fonts/win/font_fallback_win.h

@@ -33,9 +33,6 @@
 
 #include <unicode/locid.h>
 #include <unicode/uscript.h>
-#include <usp10.h>
-#include <wchar.h>
-#include <windows.h>
 
 #include "mojo/public/cpp/bindings/remote.h"
 #include "third_party/blink/public/mojom/dwrite_font_proxy/dwrite_font_proxy.mojom-blink.h"