keep only one typedef for the native drawing context

printing/printing_context_chromeos.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 PRINTING_PRINTING_CONTEXT_CHROMEOS_H_
 #define PRINTING_PRINTING_CONTEXT_CHROMEOS_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 23 matching lines @@
   gfx::Size GetPdfPaperSizeDeviceUnits() override;
   Result UpdatePrinterSettings(bool external_preview,
                                bool show_system_dialog,
                                int page_count) override;
   Result NewDocument(const base::string16& document_name) override;
   Result NewPage() override;
   Result PageDone() override;
   Result DocumentDone() override;
   void Cancel() override;
   void ReleaseContext() override;
-  gfx::NativeDrawingContext context() const override;
+  skia::NativeDrawingContext context() const override;
 
   Result StreamData(const std::vector<char>& buffer);
 
  private:
   // Lazily initializes |printer_|.
   Result InitializeDevice(const std::string& device);
 
   // id for ongoing print job.  0 if no job is active.
   int job_id_;
 
   CupsConnection connection_;
   std::unique_ptr<CupsPrinter> printer_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintingContextChromeos);
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_PRINTING_CONTEXT_CHROMEOS_H_