Re-land r93365 - add RefCountedString

base/base64.h

Index: base/base64.h
diff --git a/base/base64.h b/base/base64.h
index 294fb83a2db4ff5af0320a821ea8fbd15493f7d5..0dc2e0bfed5102510ee21933a1775f21dac44e5e 100644
--- a/base/base64.h
+++ b/base/base64.h
@@ -6,19 +6,18 @@
 #define BASE_BASE64_H__
 #pragma once
 
-#include <string>
-
 #include "base/base_api.h"
+#include "base/string_piece.h"
 
 namespace base {
 
 // Encodes the input string in base64.  Returns true if successful and false
 // otherwise.  The output string is only modified if successful.
-BASE_API bool Base64Encode(const std::string& input, std::string* output);
+BASE_API bool Base64Encode(const StringPiece& input, std::string* output);
 
 // Decodes the base64 input string.  Returns true if successful and false
 // otherwise.  The output string is only modified if successful.
-BASE_API bool Base64Decode(const std::string& input, std::string* output);
+BASE_API bool Base64Decode(const StringPiece& input, std::string* output);
 
 }  // namespace base