Move StringPiece into the base namespace. It is colliding

net/base/net_util.cc

 // Copyright (c) 2006-2008 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 <algorithm>
 #include <map>
 #include <unicode/ucnv.h>
 #include <unicode/uidna.h>
 #include <unicode/ulocdata.h>
 #include <unicode/uniset.h>
@@ skipping 900 matching lines @@
 }
 
 std::string CanonicalizeHost(const std::wstring& host,
                              url_canon::CanonHostInfo* host_info) {
   std::string converted_host;
   WideToUTF8(host.c_str(), host.length(), &converted_host);
   return CanonicalizeHost(converted_host, host_info);
 }
 
 std::string GetDirectoryListingHeader(const string16& title) {
-  static const StringPiece header(NetModule::GetResource(IDR_DIR_HEADER_HTML));
+  static const base::StringPiece header(
+      NetModule::GetResource(IDR_DIR_HEADER_HTML));
   // This can be null in unit tests.
   DLOG_IF(WARNING, header.empty()) <<
       "Missing resource: directory listing header";
 
   std::string result;
   if (!header.empty())
     result.assign(header.data(), header.size());
 
   result.append("<script>start(");
   string_escape::JsonDoubleQuote(title, true, &result);
@@ skipping 421 matching lines @@
       if (length > 0)
         ports.insert(StringToInt(WideToASCII(
             allowed_ports.substr(last, length))));
       last = i + 1;
     }
   }
   explicitly_allowed_ports = ports;
 }
 
 }  // namespace net