XFA: merge patch from CL 733693003, get rid of FX_LPCSTR cast

Get rid of FX_LPCSTR cast.

Follow up on https://codereview.chromium.org/733693003

R=brucedawson@chromium.org, tsepez@chromium.org

Review URL: https://codereview.chromium.org/809993004
diff --git a/fpdfsdk/src/javascript/PublicMethods.cpp b/fpdfsdk/src/javascript/PublicMethods.cpp
index 82bffe6..7d65249 100644
--- a/fpdfsdk/src/javascript/PublicMethods.cpp
+++ b/fpdfsdk/src/javascript/PublicMethods.cpp
@@ -443,7 +443,7 @@
 		const char * pTemp = strchr(p, ch);
 		if (pTemp == NULL)
 		{
-			StrArray.SetElement(nIndex, CJS_Value(isolate,(FX_LPCSTR)StrTrim(p)));
+			StrArray.SetElement(nIndex, CJS_Value(isolate, StrTrim(p).c_str()));
 			break;
 		}
 		else
@@ -452,7 +452,7 @@
 			strncpy(pSub, p, pTemp - p);
 			*(pSub + (pTemp - p)) = '\0';
 
-			StrArray.SetElement(nIndex, CJS_Value(isolate,(FX_LPCSTR)StrTrim(pSub)));
+			StrArray.SetElement(nIndex, CJS_Value(isolate, StrTrim(pSub).c_str()));
 			delete []pSub;
 			
 			nIndex ++;
@@ -1807,7 +1807,7 @@
 	if(!pEvent->m_pValue)
 		return FALSE;
 	CFX_WideString& Value = pEvent->Value();	
-	std::string strSrc = (FX_LPCSTR)CFX_ByteString::FromUnicode(Value);
+	std::string strSrc = CFX_ByteString::FromUnicode(Value).c_str();
 	
 	switch (iIndex) 
 	{
@@ -1962,7 +1962,7 @@
 		return FALSE;
 	//CJS_Value val = pEvent->Value();
 	CFX_WideString& val = pEvent->Value();
-	std::string strSrc = (FX_LPCSTR)CFX_ByteString::FromUnicode(val);
+	std::string strSrc = CFX_ByteString::FromUnicode(val).c_str();
 	std::wstring wstrChange(pEvent->Change());
 	
 	switch (iIndex)