Split off CPDF_Document into its own .cpp/.h files.

core/src/fpdfapi/fpdf_render/fpdf_render_cache.cpp

Index: core/src/fpdfapi/fpdf_render/fpdf_render_cache.cpp
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_cache.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_cache.cpp
index d95885f434c33e87b0ec7c64d4814bcfffb2d017..9636d1b23a3cbc00300fb3353e20d814ae8ef096 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_cache.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_cache.cpp
@@ -6,6 +6,7 @@
 
 #include "core/src/fpdfapi/fpdf_render/render_int.h"
 
+#include "core/include/fpdfapi/cpdf_document.h"
 #include "core/include/fpdfapi/fpdf_pageobj.h"
 #include "core/include/fpdfapi/fpdf_render.h"
 #include "core/include/fxge/fx_ge.h"
@@ -331,11 +332,3 @@ void CPDF_ImageCacheEntry::CalcSize() {
   m_dwCacheSize = FPDF_ImageCache_EstimateImageSize(m_pCachedBitmap) +
                   FPDF_ImageCache_EstimateImageSize(m_pCachedMask);
 }
-void CPDF_Document::ClearRenderFont() {
-  if (m_pDocRender) {
-    CFX_FontCache* pCache = m_pDocRender->GetFontCache();
-    if (pCache) {
-      pCache->FreeCache(FALSE);
-    }
-  }
-}