Use base namespace for string16 in chrome/renderer.

chrome/renderer/searchbox/searchbox_extension_unittest.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 "base/basictypes.h"
 #include "base/strings/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 namespace internal {
 
 // Defined in searchbox_extension.cc
-GURL ResolveURL(const GURL& current_url, const string16& possibly_relative_url);
+GURL ResolveURL(const GURL& current_url,
+                const base::string16& possibly_relative_url);
 
 TEST(SearchboxExtensionTest, ResolveURL) {
   EXPECT_EQ(GURL("http://www.google.com/"),
             ResolveURL(GURL(""), ASCIIToUTF16("http://www.google.com")));
 
   EXPECT_EQ(GURL("http://news.google.com/"),
             ResolveURL(GURL("http://www.google.com"),
                        ASCIIToUTF16("http://news.google.com")));
 
   EXPECT_EQ(GURL("http://www.google.com/hello?q=world"),
             ResolveURL(GURL("http://www.google.com/foo?a=b"),
                        ASCIIToUTF16("hello?q=world")));
 
   EXPECT_EQ(GURL("http://www.google.com:90/foo/hello?q=world"),
             ResolveURL(GURL("http://www.google.com:90/"),
                        ASCIIToUTF16("foo/hello?q=world")));
 }
 
 }  // namespace internal