Move operator<< for StringPiece into string_piece.{h,cc}

base/logging.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/logging.h"
 
 #if defined(OS_WIN)
 #include <io.h>
 #include <windows.h>
 typedef HANDLE FileHandle;
@@ skipping 817 matching lines @@
           break;
         }
       } while (rv != 1);
     }
   }
 
   if (level == LOG_FATAL)
     base::debug::BreakDebugger();
 }
 
+// This was defined at the beginning of this file.
+#undef write
+
 }  // namespace logging
 
 std::ostream& operator<<(std::ostream& out, const wchar_t* wstr) {
   return out << WideToUTF8(std::wstring(wstr));
 }
-
-namespace base {
-
-// This was defined at the beginnig of this file.
-#undef write
-
-std::ostream& operator<<(std::ostream& o, const StringPiece& piece) {
-  o.write(piece.data(), static_cast<std::streamsize>(piece.size()));
-  return o;
-}
-
-}  // namespace base