Use a direct include of strings headers in ppapi/, printing/.

ppapi/native_client/src/trusted/plugin/pnacl_options.cc

 // Copyright (c) 2013 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 "native_client/src/trusted/plugin/pnacl_options.h"
 
 #include <iterator>
 #include <vector>
 
 #include "native_client/src/include/nacl_string.h"
@@ skipping 27 matching lines @@
     return;
   }
   opt_level_ = l;
 }
 
 std::vector<char> PnaclOptions::GetOptCommandline() {
   std::vector<char> result;
   std::vector<nacl::string> tokens;
 
   // Split the experimental_flags_ + the -On along whitespace.
-  // Mostly a copy of "base/string_util.h", but avoid importing
+  // Mostly a copy of "base/strings/string_util.h", but avoid importing
   // base into the PPAPI plugin for now.
   nacl::string delim(" ");
   nacl::string str = experimental_flags_;
 
   if (opt_level_ != -1) {
     nacl::stringstream ss;
     // Cast as int so that it doesn't think it's a char.
     ss << " -O" << static_cast<int>(opt_level_);
     str += ss.str();
   }
@@ skipping 14 matching lines @@
     nacl::string t = tokens[i];
     result.reserve(result.size() + t.size());
     std::copy(t.begin(), t.end(), std::back_inserter(result));
     result.push_back('\x00');
   }
 
   return result;
 }
 
 }  // namespace plugin