Cleanup string passing in core/fpdf*

Return strings where possible.
Add missing consts to strings passed by ref.
Convert non-const cases to pointers.
Rename a few methods to be clearer.

Change-Id: I86569bc1744f539e6dd67fc73649b272c016328c
Reviewed-on: https://pdfium-review.googlesource.com/3951
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Nicolás Peña <npm@chromium.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/core/fpdfapi/parser/cpdf_crypto_handler.cpp b/core/fpdfapi/parser/cpdf_crypto_handler.cpp
index 4fc7b3039b..ea09601b30 100644
--- a/core/fpdfapi/parser/cpdf_crypto_handler.cpp
+++ b/core/fpdfapi/parser/cpdf_crypto_handler.cpp
@@ -227,14 +227,14 @@ bool CPDF_CryptoHandler::CryptFinish(void* context,
   return true;
 }
 
-void CPDF_CryptoHandler::Decrypt(uint32_t objnum,
-                                 uint32_t gennum,
-                                 CFX_ByteString& str) {
+CFX_ByteString CPDF_CryptoHandler::Decrypt(uint32_t objnum,
+                                           uint32_t gennum,
+                                           const CFX_ByteString& str) {
   CFX_BinaryBuf dest_buf;
   void* context = DecryptStart(objnum, gennum);
   DecryptStream(context, str.raw_str(), str.GetLength(), dest_buf);
   DecryptFinish(context, dest_buf);
-  str = CFX_ByteString(dest_buf.GetBuffer(), dest_buf.GetSize());
+  return CFX_ByteString(dest_buf.GetBuffer(), dest_buf.GetSize());
 }
 
 void* CPDF_CryptoHandler::DecryptStart(uint32_t objnum, uint32_t gennum) {