Fix illegal cast in core/fxge/win32/fx_win32_gdipext.cpp

Bug: pdfium:243
Change-Id: I36ebe64daa042b998878ffacfca9846b5303450b
Reviewed-on: https://pdfium-review.googlesource.com/31652
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fxge/win32/fx_win32_gdipext.cpp b/core/fxge/win32/fx_win32_gdipext.cpp
index a83a449..eee6b87 100644
--- a/core/fxge/win32/fx_win32_gdipext.cpp
+++ b/core/fxge/win32/fx_win32_gdipext.cpp
@@ -1165,7 +1165,8 @@
 void CGdiplusExt::DeleteMemFont(LPVOID pCollection) {
   CGdiplusExt& GdiplusExt =
       ((CWin32Platform*)CFX_GEModule::Get()->GetPlatformData())->m_GdiplusExt;
-  CallFunc(GdipDeletePrivateFontCollection)((GpFontCollection**)&pCollection);
+  auto* pActualType = static_cast<GpFontCollection*>(pCollection);
+  CallFunc(GdipDeletePrivateFontCollection)(&pActualType);
 }
 bool CGdiplusExt::GdipCreateBitmap(const RetainPtr<CFX_DIBitmap>& pBitmap,
                                    void** bitmap) {