Make CPDF_Object::GetString() a virtual method.

core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp

Index: core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index 0ee7a0da7d0d8b3f9de19d723f14e6d7e8162756..68c25facd8a87c2736223bff269a4f5c4db4977b 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -813,7 +813,7 @@ FX_BOOL CPDF_IndexedCS::v_Load(CPDF_Document* pDoc, CPDF_Array* pArray)
         return FALSE;
     }
     if (pTableObj->GetType() == PDFOBJ_STRING) {
-        m_Table = ((CPDF_String*)pTableObj)->GetString();
+        m_Table = pTableObj->GetString();
     } else if (pTableObj->GetType() == PDFOBJ_STREAM) {
         CPDF_StreamAcc acc;
         acc.LoadAllData((CPDF_Stream*)pTableObj, FALSE);
@@ -940,7 +940,7 @@ void CPDF_SeparationCS::GetDefaultValue(int iComponent, FX_FLOAT& value, FX_FLOA
 }
 FX_BOOL CPDF_SeparationCS::v_Load(CPDF_Document* pDoc, CPDF_Array* pArray)
 {
-    CFX_ByteString name = pArray->GetString(1);
+    CFX_ByteString name = pArray->GetStringAt(1);
     if (name == FX_BSTRC("None")) {
         m_Type = None;
     } else {