Revert of Adding StringPiece read/write support to pickle.

base/pickle.h

Index: base/pickle.h
diff --git a/base/pickle.h b/base/pickle.h
index b9b41267153e4f0f318440fef4304ce0462176b7..f2a198e3f2da9e13be0b4e20f1fcf8460133327b 100644
--- a/base/pickle.h
+++ b/base/pickle.h
@@ -13,7 +13,6 @@
 #include "base/gtest_prod_util.h"
 #include "base/logging.h"
 #include "base/strings/string16.h"
-#include "base/strings/string_piece.h"
 
 class Pickle;
 
@@ -40,12 +39,8 @@
   bool ReadFloat(float* result) WARN_UNUSED_RESULT;
   bool ReadDouble(double* result) WARN_UNUSED_RESULT;
   bool ReadString(std::string* result) WARN_UNUSED_RESULT;
-  // The StringPiece data will only be valid for the lifetime of the message.
-  bool ReadStringPiece(base::StringPiece* result) WARN_UNUSED_RESULT;
   bool ReadWString(std::wstring* result) WARN_UNUSED_RESULT;
   bool ReadString16(base::string16* result) WARN_UNUSED_RESULT;
-  // The StringPiece16 data will only be valid for the lifetime of the message.
-  bool ReadStringPiece16(base::StringPiece16* result) WARN_UNUSED_RESULT;
 
   // A pointer to the data will be placed in |*data|, and the length will be
   // placed in |*length|. The pointer placed into |*data| points into the
@@ -200,9 +195,9 @@
   bool WriteDouble(double value) {
     return WritePOD(value);
   }
-  bool WriteString(const base::StringPiece& value);
+  bool WriteString(const std::string& value);
   bool WriteWString(const std::wstring& value);
-  bool WriteString16(const base::StringPiece16& value);
+  bool WriteString16(const base::string16& value);
   // "Data" is a blob with a length. When you read it out you will be given the
   // length. See also WriteBytes.
   bool WriteData(const char* data, int length);