Printing: Convert PrintingContext into an interface implemented by the separate

printing/printing_context_cairo.h

Index: printing/printing_context_cairo.h
diff --git a/printing/printing_context_cairo.h b/printing/printing_context_cairo.h
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index 0000000000000000000000000000000000000000..d4c98caf7015f1b4af9929ef591c57f6220019f0
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+++ b/printing/printing_context_cairo.h
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+// Copyright (c) 2010 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_CAIRO_H_
+#define PRINTING_PRINTING_CONTEXT_CAIRO_H_
+
+#include "printing/printing_context.h"
+
+namespace printing {
+
+class PrintingContextCairo : public PrintingContext {
+ public:
+  PrintingContextCairo();
+  ~PrintingContextCairo();
+
+  // PrintingContext implementation.
+  virtual void AskUserForSettings(gfx::NativeView parent_view,
+                                  int max_pages,
+                                  bool has_selection,
+                                  PrintSettingsCallback* callback);
+  virtual Result UseDefaultSettings();
+  virtual Result InitWithSettings(const PrintSettings& settings);
+  virtual Result NewDocument(const string16& document_name);
+  virtual Result NewPage();
+  virtual Result PageDone();
+  virtual Result DocumentDone();
+  virtual void Cancel();
+  virtual void DismissDialog();
+  virtual void ReleaseContext();
+  virtual gfx::NativeDrawingContext context() const;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PrintingContextCairo);
+};
+
+}  // namespace printing
+
+#endif  // PRINTING_PRINTING_CONTEXT_CAIRO_H_