base: Update the include paths of base/string_piece.h to its new location.

base/strings/utf_offset_string_conversions_unittest.cc

 // Copyright (c) 2011 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 "base/logging.h"
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/utf_offset_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
 namespace {
 
 static const size_t kNpos = string16::npos;
 
 }  // namespace
@@ skipping 126 matching lines @@
     }
     size_t expected_3[] = {kNpos, kNpos, kNpos, 0, 1, kNpos, kNpos, kNpos, 5, 6,
                            7, 8, kNpos, kNpos, 11, kNpos, kNpos};
     EXPECT_EQ(offsets.size(), arraysize(expected_3));
     for (size_t i = 0; i < arraysize(expected_3); ++i)
       EXPECT_EQ(expected_3[i], offsets[i]);
   }
 }
 
 }  // namaspace base