Make chromeos CUPS printing code namespaces consistent.

chromeos/printing/ppd_cache.h

 // Copyright 2016 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 CHROMEOS_PRINTING_PPD_CACHE_H_
 #define CHROMEOS_PRINTING_PPD_CACHE_H_
 
 #include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
 #include "chromeos/chromeos_export.h"
 
 namespace chromeos {
-namespace printing {
 
 // PpdCache manages a cache of locally-stored PPD files.  At its core, it
 // operates like a persistent hash from PpdReference to files.  If you give the
 // same PpdReference to Find() that was previously given to store, you should
 // get the same FilePath back out (unless the previous entry has timed out of
 // the cache).  However, changing *any* field in PpdReference will make the
 // previous cache entry invalid.  This is the intentional behavior -- we want to
 // re-run the resolution logic if we have new meta-information about a printer.
 //
 // All cache functions must be called on a thread which is permitted to do I/O.
@@ skipping 26 matching lines @@
   // be invoked on completion.
   virtual void Store(const std::string& key,
                      const std::string& contents,
                      const base::Closure& cb) = 0;
 
  protected:
   friend class base::RefCounted<PpdCache>;
   virtual ~PpdCache() {}
 };
 
-}  // namespace printing
 }  // namespace chromeos
 
 #endif  // CHROMEOS_PRINTING_PPD_CACHE_H_