gdi32: Check for NULL pointer in GetOutlineTextMetrics.

dlls/gdi32/freetype.c

@@ -7722,7 +7722,7 @@ static UINT freetype_GetOutlineTextMetrics( PHYSDEV dev, UINT cbSize, OUTLINETEX
 
     if (physdev->font->potm || get_outline_text_metrics( physdev->font ))
     {
-        if(cbSize >= physdev->font->potm->otmSize)
+        if(potm && cbSize >= physdev->font->potm->otmSize)
         {
 	    memcpy(potm, physdev->font->potm, physdev->font->potm->otmSize);
             scale_outline_font_metrics(physdev->font, potm);

dlls/gdi32/tests/font.c

@@ -2147,6 +2147,11 @@ static void test_GetOutlineTextMetrics(void)
     }
     ok(otm->otmpFullName == unset_ptr, "expected %p got %p\n", unset_ptr, otm->otmpFullName);
 
+    /* check handling of NULL pointer */
+    SetLastError(0xdeadbeef);
+    ret = GetOutlineTextMetricsA(hdc, otm_size, NULL);
+    ok(ret == otm_size, "expected %u, got %u, error %d\n", otm_size, ret, GetLastError());
+
     HeapFree(GetProcessHeap(), 0, otm);
 
     SelectObject(hdc, hfont_old);