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

base/test/expectations/parser.h

 // 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.
 
 #ifndef BASE_TEST_EXPECTATIONS_PARSER_H_
 #define BASE_TEST_EXPECTATIONS_PARSER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 #include "base/test/expectations/expectation.h"
 
 namespace test_expectations {
 
 // This is the internal parser for test expectations. It parses an input
 // string and reports information to its Delegate as it's processing the
 // input.
 //
 // The input format is documented here:
 // https://docs.google.com/a/chromium.org/document/d/1edhMJ5doY_dzfbKNCzeJJ-8XxPrexTbNL2Y_jVvLB8Q/view
@@ skipping 112 matching lines @@
   Expectation current_;
 
   // If DataError() has been called during the course of parsing |current_|.
   // If true, then |current_| will not be emitted to the Delegate.
   bool data_error_;
 };
 
 }  // namespace test_expectations
 
 #endif  // BASE_TEST_EXPECTATIONS_PARSER_H_