Include USB printers in printer list as "provisional" devices.

chrome/browser/ui/webui/print_preview/printer_handler.h

Index: chrome/browser/ui/webui/print_preview/printer_handler.h
diff --git a/chrome/browser/ui/webui/print_preview/printer_handler.h b/chrome/browser/ui/webui/print_preview/printer_handler.h
index 7882e4967025c2689eea89cd7bb025e88837c2d8..d4faf21e38c0c07244edaf7aa9bb2ff67f89c9a0 100644
--- a/chrome/browser/ui/webui/print_preview/printer_handler.h
+++ b/chrome/browser/ui/webui/print_preview/printer_handler.h
@@ -40,10 +40,6 @@ class PrinterHandler {
   using PrintCallback =
       base::Callback<void(bool success, const std::string& error)>;
 
-  // Creates an instance of an PrinterHandler for extension printers.
-  static scoped_ptr<PrinterHandler> CreateForExtensionPrinters(
-      content::BrowserContext* browser_context);
-
   virtual ~PrinterHandler() {}
 
   // Cancels all pending requests.