Move StringPiece into the base namespace. It is colliding

net/url_request/url_request_unittest.cc

 // Copyright (c) 2006-2009 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/url_request/url_request_unittest.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
@@ skipping 60 matching lines @@
 };
 
 class TestURLRequest : public URLRequest {
  public:
   TestURLRequest(const GURL& url, Delegate* delegate)
       : URLRequest(url, delegate) {
     set_context(new URLRequestTestContext());
   }
 };
 
-StringPiece TestNetResourceProvider(int key) {
+base::StringPiece TestNetResourceProvider(int key) {
   return "header";
 }
 
 // Do a case-insensitive search through |haystack| for |needle|.
 bool ContainsString(const std::string& haystack, const char* needle) {
   std::string::const_iterator it =
       std::search(haystack.begin(),
                   haystack.end(),
                   needle,
                   needle + strlen(needle),
@@ skipping 2001 matching lines @@
 
     int64 file_size = 0;
     file_util::GetFileSize(app_path, &file_size);
 
     EXPECT_FALSE(r.is_pending());
     EXPECT_EQ(1, d.response_started_count());
     EXPECT_FALSE(d.received_data_before_response());
     EXPECT_EQ(d.bytes_received(), static_cast<int>(file_size));
   }
 }