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

ui/base/resource/data_pack.h

 // Copyright (c) 2012 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.
 
 // DataPack represents a read-only view onto an on-disk file that contains
 // (key, value) pairs of data.  It's used to store static resources like
 // translation strings and images.
 
 #ifndef UI_BASE_RESOURCE_DATA_PACK_H_
 #define UI_BASE_RESOURCE_DATA_PACK_H_
 
 #include <map>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/platform_file.h"
-#include "base/string_piece.h"
+#include "base/strings/string_piece.h"
 #include "ui/base/layout.h"
 #include "ui/base/resource/resource_handle.h"
 #include "ui/base/ui_export.h"
 
 namespace base {
 class FilePath;
 class MemoryMappedFile;
 class RefCountedStaticMemory;
 }
 
@@ skipping 43 matching lines @@
   // The scale of the image in this resource pack relative to images in the 1x
   // resource pak.
   ui::ScaleFactor scale_factor_;
 
   DISALLOW_COPY_AND_ASSIGN(DataPack);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_RESOURCE_DATA_PACK_H_