Move StringPiece into the base namespace. It is colliding

base/string_piece.h

Index: base/string_piece.h
diff --git a/base/string_piece.h b/base/string_piece.h
index fe108069c706a58c60fb8ef7f1a7551893081d37..47d49684548f62d99b9ce7af33947e05cba17ec1 100644
--- a/base/string_piece.h
+++ b/base/string_piece.h
@@ -24,6 +24,8 @@
 
 #include "base/basictypes.h"
 
+namespace base {
+
 class StringPiece {
  public:
   typedef size_t size_type;
@@ -181,4 +183,6 @@ inline bool operator>=(const StringPiece& x, const StringPiece& y) {
 // allow StringPiece to be logged (needed for unit testing).
 extern std::ostream& operator<<(std::ostream& o, const StringPiece& piece);
 
+}  // namespace base
+
 #endif  // BASE_STRING_PIECE_H_