Add onGetUsbPrinterInfoRequested event to printerProvider API.

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

Index: chrome/browser/ui/webui/print_preview/print_preview_handler.h
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_handler.h b/chrome/browser/ui/webui/print_preview/print_preview_handler.h
index 356678bed9cdcfc9340d98f5e06ebf06e64f4629..f86f835c7c7213f5afb2d74b6403968f07fcf9b9 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.h
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.h
@@ -133,6 +133,10 @@ class PrintPreviewHandler
   // unused.
   void HandleGetExtensionUsbPrinters(const base::ListValue* args);
 
+  // Grants an extension access to a USB printer.  First element of |args| is
+  // the extension ID and the second element is USB device ID.
+  void HandleGrantExtensionUsbPrinterAccess(const base::ListValue* args);
+
   // Stops getting all local privet printers. |arg| is unused.
   void HandleStopGetPrivetPrinters(const base::ListValue* args);
 
@@ -317,6 +321,15 @@ class PrintPreviewHandler
   // |printers|: The list of printers supported by extensions.
   void OnGotExtensionUsbPrinters(const base::ListValue& printers);
 
+  // Called when an extension reports information for a USB printer it has just
+  // been granted access to.
+  // |extension_id|: The extension that was queried.
+  // |device_id|: The id of the USB device.
+  // |printer_info|: The data reported by the extension.
+  void OnGotExtensionUsbPrinterInfo(const std::string& extension_id,
+                                    int device_id,
+                                    const base::DictionaryValue& printer_info);
+
   // Called when an extension reports the set of print capabilites for a
   // printer.
   // |printer_id|: The id of the printer whose capabilities are reported.