Bug 1852806 - Remove macros for older Windows SDK from mozglue/. r=glandium

Depends on D188026

Differential Revision: https://phabricator.services.mozilla.com/D188027

mozglue/misc/WindowsDpiAwareness.h

@@ -28,11 +28,6 @@ typedef enum DPI_AWARENESS {
 #  define DPI_AWARENESS_CONTEXT_DECLARED
 #endif  // (DPI_AWARENESS_CONTEXT_DECLARED)
 
-#if WINVER < 0x0605
-WINUSERAPI DPI_AWARENESS_CONTEXT WINAPI GetThreadDpiAwarenessContext();
-WINUSERAPI BOOL WINAPI AreDpiAwarenessContextsEqual(DPI_AWARENESS_CONTEXT,
-                                                    DPI_AWARENESS_CONTEXT);
-#endif /* WINVER < 0x0605 */
 typedef DPI_AWARENESS_CONTEXT(WINAPI* SetThreadDpiAwarenessContextProc)(
     DPI_AWARENESS_CONTEXT);
 typedef BOOL(WINAPI* EnableNonClientDpiScalingProc)(HWND);

mozglue/misc/WindowsProcessMitigations.cpp

@@ -13,12 +13,6 @@
 
 static_assert(sizeof(PROCESS_MITIGATION_DYNAMIC_CODE_POLICY) == 4);
 
-#if (_WIN32_WINNT < 0x0602)
-BOOL WINAPI GetProcessMitigationPolicy(
-    HANDLE hProcess, PROCESS_MITIGATION_POLICY MitigationPolicy, PVOID lpBuffer,
-    SIZE_T dwLength);
-#endif  // (_WIN32_WINNT < 0x0602)
-
 namespace mozilla {
 
 static decltype(&::GetProcessMitigationPolicy)