Add SpdyString alias for std::string in net/spdy.

net/spdy/spdy_framer_decoder_adapter.cc

 // Copyright (c) 2016 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 "net/spdy/spdy_framer_decoder_adapter.h"
 
 #include <memory>
-#include <string>
 #include <utility>
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "net/spdy/platform/api/spdy_estimate_memory_usage.h"
 #include "net/spdy/platform/api/spdy_string_utils.h"
 
 #if defined(COMPILER_GCC)
 #define PRETTY_THIS SpdyStringPrintf("%s@%p ", __PRETTY_FUNCTION__, this)
 #elif defined(COMPILER_MSVC)
@@ skipping 224 matching lines @@
   std::unique_ptr<SpdyFramerVisitorAdapter> visitor_adapter_;
 };
 
 std::unique_ptr<SpdyFramerDecoderAdapter> CreateNestedSpdyFramerDecoder(
     SpdyFramer* outer) {
   return std::unique_ptr<SpdyFramerDecoderAdapter>(
       new NestedSpdyFramerDecoder(outer));
 }
 
 }  // namespace net