Disable NativeWindow screen read capability on non-win32 platform NativeWindow::readScreenPixels() only returns true on win32 platform. Enable CAPABILITY_READ_SCREEN_PIXELS on DE_OS_WIN32 only. Bug: b/296487949 Bug: angleproject:8261 Change-Id: I964870a3a5c6911a16382e2b9bb9d2cecea2b706 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4794979 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Roman Lavrov <romanl@google.com> Commit-Queue: Yuxin Hu <yuxinhu@google.com>