Cleanup: Use base namespace in printing/.

printing/print_dialog_gtk_interface.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.
 
 #ifndef PRINTING_PRINT_DIALOG_GTK_INTERFACE_H_
 #define PRINTING_PRINT_DIALOG_GTK_INTERFACE_H_
 
 #include "base/strings/string16.h"
 #include "printing/printing_context_gtk.h"
 #include "ui/gfx/native_widget_types.h"
@@ skipping 23 matching lines @@
   // printing with the native print dialog.
   virtual void ShowDialog(
       gfx::NativeView parent_view,
       bool has_selection,
       const PrintingContextGtk::PrintSettingsCallback& callback) = 0;
 
   // Prints the document named |document_name| contained in |metafile|.
   // Called from the print worker thread. Once called, the
   // PrintDialogGtkInterface instance should not be reused.
   virtual void PrintDocument(const Metafile* metafile,
-                             const string16& document_name) = 0;
+                             const base::string16& document_name) = 0;
 
   // Same as AddRef/Release, but with different names since
   // PrintDialogGtkInterface does not inherit from RefCounted.
   virtual void AddRefToDialog() = 0;
   virtual void ReleaseDialog() = 0;
 
  protected:
   virtual ~PrintDialogGtkInterface() {}
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_PRINT_DIALOG_GTK_INTERFACE_H_