Move StringPiece into the base namespace. It is colliding

net/base/net_module.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 "net/base/net_module.h"
 
 namespace net {
 
 static NetModule::ResourceProvider resource_provider;
 
 // static
 void NetModule::SetResourceProvider(ResourceProvider func) {
   resource_provider = func;
 }
 
 // static
-StringPiece NetModule::GetResource(int key) {
-  return resource_provider ? resource_provider(key) : StringPiece();
+base::StringPiece NetModule::GetResource(int key) {
+  return resource_provider ? resource_provider(key) : base::StringPiece();
 }
 
 }  // namespace net