Make the PDF viewer background color a property of the instance.

pdf/pdf_engine.h

Index: pdf/pdf_engine.h
diff --git a/pdf/pdf_engine.h b/pdf/pdf_engine.h
index e8434595ddb5edd0202329404cd26839d433611f..befb1b82cf04951f62f35f6b08c5c08527f2c4f8 100644
--- a/pdf/pdf_engine.h
+++ b/pdf/pdf_engine.h
@@ -173,6 +173,9 @@ class PDFEngine {
 
     // Returns true if the plugin has been opened within print preview.
     virtual bool IsPrintPreview() = 0;
+
+    // Get the background color of the PDF.
+    virtual uint32 GetBackgroundColor() = 0;
   };
 
   // Factory method to create an instance of the PDF Engine.
@@ -246,11 +249,6 @@ class PDFEngine {
   // Returns number of copies to be printed.
   virtual int GetCopiesToPrint() = 0;
 
-  // Retrieve the background color of the PDF viewer.
-  virtual uint32 GetBackgroundColor() = 0;
-  // Set the background color of the PDF viewer.
-  virtual void SetBackgroundColor(uint32 background_color) = 0;
-
   // Returns a VarArray of Bookmarks, each a VarDictionary containing the
   // following key/values:
   // - "title" - a string Var.