Get rid of NULLs in core/

core/fpdfapi/fpdf_page/cpdf_textstate.cpp

Index: core/fpdfapi/fpdf_page/cpdf_textstate.cpp
diff --git a/core/fpdfapi/fpdf_page/cpdf_textstate.cpp b/core/fpdfapi/fpdf_page/cpdf_textstate.cpp
index 5269cae44b2b8aca52df208e59d0b34fac381aa6..50fc7789fef16a09d5e1100e8ddf93e15e101634 100644
--- a/core/fpdfapi/fpdf_page/cpdf_textstate.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_textstate.cpp
@@ -13,11 +13,11 @@ void CPDF_TextState::SetFont(CPDF_Font* pFont) {
   CPDF_TextStateData* pStateData = GetModify();
   if (pStateData) {
     CPDF_Document* pDoc = pStateData->m_pDocument;
-    CPDF_DocPageData* pPageData = pDoc ? pDoc->GetPageData() : NULL;
+    CPDF_DocPageData* pPageData = pDoc ? pDoc->GetPageData() : nullptr;
     if (pPageData && pStateData->m_pFont && !pPageData->IsForceClear()) {
       pPageData->ReleaseFont(pStateData->m_pFont->GetFontDict());
     }
-    pStateData->m_pDocument = pFont ? pFont->m_pDocument : NULL;
+    pStateData->m_pDocument = pFont ? pFont->m_pDocument : nullptr;
     pStateData->m_pFont = pFont;
   }
 }