Convert protected members to private in CPDF_RenderContext.

CPDF_RenderContext is not extended by any subclasses.

Change-Id: I6bb79f1c681fe28a3d7444e1416f0c14e51daef1
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/96450
Commit-Queue: Lei Zhang <thestig@chromium.org>
Auto-Submit: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fpdfapi/render/cpdf_rendercontext.h b/core/fpdfapi/render/cpdf_rendercontext.h
index b2c0bf0..8a03d44 100644
--- a/core/fpdfapi/render/cpdf_rendercontext.h
+++ b/core/fpdfapi/render/cpdf_rendercontext.h
@@ -72,7 +72,7 @@
   }
   CPDF_PageRenderCache* GetPageCache() const { return m_pPageCache.Get(); }
 
- protected:
+ private:
   UnownedPtr<CPDF_Document> const m_pDocument;
   RetainPtr<CPDF_Dictionary> const m_pPageResources;
   UnownedPtr<CPDF_PageRenderCache> const m_pPageCache;