uxtheme: Add a stub for IsCompositionActive().

dlls/uxtheme/system.c

@@ -562,6 +562,18 @@ BOOL WINAPI IsThemeActive(void)
     return bThemeActive;
 }
 
+/************************************************************
+*       IsCompositionActive   (UXTHEME.@)
+*/
+BOOL WINAPI IsCompositionActive(void)
+{
+    FIXME(": stub\n");
+
+    SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
+
+    return FALSE;
+}
+
 /***********************************************************************
  *      EnableTheming                                       (UXTHEME.@)
  *

dlls/uxtheme/uxtheme.spec

@@ -100,6 +100,7 @@
 @ stdcall GetWindowTheme(ptr)
 @ stdcall HitTestThemeBackground(ptr long long long long ptr long int64 ptr)
 @ stdcall IsAppThemed()
+@ stdcall IsCompositionActive()
 @ stdcall IsThemeActive()
 @ stdcall IsThemeBackgroundPartiallyTransparent(ptr long long)
 @ stdcall IsThemeDialogTextureEnabled(ptr)

include/uxtheme.h

@@ -209,6 +209,7 @@ HTHEME WINAPI GetWindowTheme(HWND);
 HRESULT WINAPI HitTestThemeBackground(HTHEME,HDC,int,int,DWORD,const RECT*,
                                       HRGN,POINT,WORD*);
 BOOL WINAPI IsAppThemed(void);
+BOOL WINAPI IsCompositionActive(void);
 BOOL WINAPI IsThemeActive(void);
 BOOL WINAPI IsThemeBackgroundPartiallyTransparent(HTHEME,int,int);
 BOOL WINAPI IsThemeDialogTextureEnabled(HWND);