Bug 1852806 - Remove macros for older Windows SDK from browser/components/shell/. r=nalexander

Depends on D188019

Differential Revision: https://phabricator.services.mozilla.com/D188020

browser/components/shell/WindowsDefaultBrowser.cpp

@@ -15,15 +15,8 @@
 #include "mozilla/WindowsVersion.h"
 #include "mozilla/WinHeaderOnlyUtils.h"
 
-// Needed for access to IApplicationActivationManager
 // This must be before any other includes that might include shlobj.h
-#ifdef _WIN32_WINNT
-#  undef _WIN32_WINNT
-#endif
-#define _WIN32_WINNT 0x0600
 #define INITGUID
-#undef NTDDI_VERSION
-#define NTDDI_VERSION NTDDI_WIN8
 #include <shlobj.h>
 
 #include <lm.h>