net: Update the include paths of base/string_piece.h to its new location.

net/spdy/spdy_frame_builder.h

 // 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.
 
 #ifndef NET_SPDY_SPDY_FRAME_BUILDER_H_
 #define NET_SPDY_SPDY_FRAME_BUILDER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 #include "base/sys_byteorder.h"
 #include "net/base/net_export.h"
 #include "net/spdy/spdy_protocol.h"
 
 namespace net {
 
 class SpdyFramer;
 
 // This class provides facilities for basic binary value packing
 // into Spdy frames.
@@ skipping 87 matching lines @@
   bool CanWrite(size_t length) const;
 
   scoped_ptr<char[]> buffer_;
   size_t capacity_;  // Allocation size of payload, set by constructor.
   size_t length_;    // Current length of the buffer.
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_FRAME_BUILDER_H_