Make CPDF_Object::GetString() a virtual method.

core/src/fpdfdoc/doc_ocg.cpp

Index: core/src/fpdfdoc/doc_ocg.cpp
diff --git a/core/src/fpdfdoc/doc_ocg.cpp b/core/src/fpdfdoc/doc_ocg.cpp
index 8477cb85d02c83fcd733f062b3679a94656f07be..fd1613a409c99d33a9b3e54466e091ca03a8368f 100644
--- a/core/src/fpdfdoc/doc_ocg.cpp
+++ b/core/src/fpdfdoc/doc_ocg.cpp
@@ -36,7 +36,7 @@ static FX_BOOL FPDFDOC_OCG_HasIntent(const CPDF_Dictionary *pDict, const CFX_Byt
     if (pIntent->GetType() == PDFOBJ_ARRAY) {
         FX_DWORD dwCount = ((CPDF_Array*)pIntent)->GetCount();
         for (FX_DWORD i = 0; i < dwCount; i++) {
-            bsIntent = ((CPDF_Array*)pIntent)->GetString(i);
+            bsIntent = ((CPDF_Array*)pIntent)->GetStringAt(i);
             if (bsIntent == FX_BSTRC("All") || bsIntent == csElement) {
                 return TRUE;
             }
@@ -108,7 +108,7 @@ FX_BOOL CPDF_OCContext::LoadOCGStateFromConfig(const CFX_ByteStringC& csConfig,
         return TRUE;
     }
     bValidConfig = TRUE;
-    FX_BOOL bState = pConfig->GetString(FX_BSTRC("BaseState"), FX_BSTRC("ON")) != FX_BSTRC("OFF");
+    FX_BOOL bState = pConfig->GetStringAt("BaseState", "ON") != "OFF";
     CPDF_Array *pArray = pConfig->GetArray(FX_BSTRC("ON"));
     if (pArray) {
         if (FPDFDOC_OCG_FindGroup(pArray, pOCGDict) >= 0) {
@@ -130,7 +130,7 @@ FX_BOOL CPDF_OCContext::LoadOCGStateFromConfig(const CFX_ByteStringC& csConfig,
             if (!pUsage) {
                 continue;
             }
-            if (pUsage->GetString(FX_BSTRC("Event"), FX_BSTRC("View")) != csConfig) {
+            if (pUsage->GetStringAt("Event", "View") != csConfig) {
                 continue;
             }
             CPDF_Array *pOCGs = pUsage->GetArray(FX_BSTRC("OCGs"));
@@ -144,7 +144,7 @@ FX_BOOL CPDF_OCContext::LoadOCGStateFromConfig(const CFX_ByteStringC& csConfig,
             if (!pState) {
                 continue;
             }
-            bState = pState->GetString(csFind) != FX_BSTRC("OFF");
+            bState = pState->GetStringAt(csFind) != "OFF";
         }
     }
     return bState;
@@ -161,13 +161,13 @@ FX_BOOL CPDF_OCContext::LoadOCGState(const CPDF_Dictionary *pOCGDict) const
         if (pState) {
             CFX_ByteString csFind = csState + FX_BSTRC("State");
             if (pState->KeyExist(csFind)) {
-                return pState->GetString(csFind) != FX_BSTRC("OFF");
+                return pState->GetStringAt(csFind) != "OFF";
             }
         }
         if (csState != FX_BSTRC("View")) {
             pState = pUsage->GetDict(FX_BSTRC("View"));
             if (pState && pState->KeyExist(FX_BSTRC("ViewState"))) {
-                return pState->GetString(FX_BSTRC("ViewState")) != FX_BSTRC("OFF");
+                return pState->GetStringAt("ViewState") != "OFF";
             }
         }
     }
@@ -199,7 +199,7 @@ FX_BOOL CPDF_OCContext::GetOCGVE(CPDF_Array *pExpression, FX_BOOL bFromConfig, i
     }
     int32_t iCount = pExpression->GetCount();
     CPDF_Object *pOCGObj;
-    CFX_ByteString csOperator = pExpression->GetString(0);
+    CFX_ByteString csOperator = pExpression->GetStringAt(0);
     if (csOperator == FX_BSTRC("Not")) {
         pOCGObj = pExpression->GetElementValue(1);
         if (pOCGObj == NULL) {
@@ -247,7 +247,7 @@ FX_BOOL CPDF_OCContext::LoadOCMDState(const CPDF_Dictionary *pOCMDDict, FX_BOOL
     if (pVE != NULL) {
         return GetOCGVE(pVE, bFromConfig);
     }
-    CFX_ByteString csP = pOCMDDict->GetString(FX_BSTRC("P"), FX_BSTRC("AnyOn"));
+    CFX_ByteString csP = pOCMDDict->GetStringAt("P", "AnyOn");
     CPDF_Object *pOCGObj = pOCMDDict->GetElementValue(FX_BSTRC("OCGs"));
     if (pOCGObj == NULL) {
         return TRUE;
@@ -289,7 +289,7 @@ FX_BOOL CPDF_OCContext::CheckOCGVisible(const CPDF_Dictionary *pOCGDict)
     if (pOCGDict == NULL) {
         return TRUE;
     }
-    CFX_ByteString csType = pOCGDict->GetString(FX_BSTRC("Type"), FX_BSTRC("OCG"));
+    CFX_ByteString csType = pOCGDict->GetStringAt("Type", "OCG");
     if (csType == FX_BSTRC("OCG")) {
         return GetOCGVisible(pOCGDict);
     } else {