Add onGetUsbPrinterInfoRequested event to printerProvider API.

extensions/common/api/printer_provider.idl

 // Copyright 2014 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.
 
 // The <code>chrome.printerProvider</code> API exposes events used by print
 // manager to query printers controlled by extensions, to query their
 // capabilities and to submit print jobs to these printers.
 namespace printerProvider {
   // Error codes returned in response to $(ref:onPrintRequested) event.
   enum PrintError {
@@ skipping 16 matching lines @@
   // Printer description for $(ref:onGetPrintersRequested) event.
   dictionary PrinterInfo {
     // Unique printer ID.
     DOMString id;
 
     // Printer's human readable name.
     DOMString name;
 
     // Printer's human readable description.
     DOMString? description;
+
+    // USB device corresponding to this printer. This should be the
+    // opaque ID found in the $(ref:usb.Device) dictionary.
+    long? usbDevice;
   };
 
   // Printing request parameters. Passed to $(ref:onPrintRequested) event.
   dictionary PrintJob {
     // ID of the printer which should handle the job.
     DOMString printerId;
 
     // The print job title.
     DOMString title;
 
     // Print ticket in
     // <a href="https://developers.google.com/cloud-print/docs/cdd#cjt">
     // CJT format</a>.
     object ticket;
 
     // The document content type. Supported formats are
     // <code>"application/pdf"</code> and <code>"image/pwg-raster"</code>.
     DOMString contentType;
 
     // Blob containing the document data to print. Format must match
     // |contentType|.
     [instanceOf=Blob] object document;
   };
 
   callback PrintersCallback = void(PrinterInfo[] printerInfo);
 
+  callback PrinterInfoCallback = void(PrinterInfo printerInfo);
+
   // |capabilities|: Device capabilities in
   // <a href="https://developers.google.com/cloud-print/docs/cdd#cdd">CDD
   // format</a>.
   callback CapabilitiesCallback = void(object capabilities);
 
   callback PrintCallback = void(PrintError result);
 
   interface Events {
     // Event fired when print manager requests printers provided by extensions.
     // |resultCallback|: Callback to return printer list. Every listener must
     // call callback exactly once.
     static void onGetPrintersRequested(PrintersCallback resultCallback);
 
+    // Event fired when print manager grants access to a USB device.
+    // |device|: The USB device.
+    // |resultCallback|: Callback to return printer info. The receiving listener
+    // must call callback exactly once. If the parameter to this callback is
+    // undefined that indicates that the application has determined that the

[Vitaly Buka (NO REVIEWS), 2015/05/21 00:52:02]

Looks like this even should be in chrome.usb

Idea was to have printerProvider independent form printer implementation.

[Reilly Grant (use Gerrit), 2015/05/21 00:58:22]

I could add this event to chrome.usb but I would no longer want it to provide a
PrinterInfoCallback. Instead I would add a printerAdded function to
chrome.printerProvider so that providers could add printers to the print preview
dialog outside the context of an enumeration. This would also be useful for when
a printer is connected after the print dialog is opened. What do you think?

+    // device is not supported.
+    static void onUsbAccessGranted(usb.Device device,
+                                   PrinterInfoCallback resultCallback);
+
     // Event fired when print manager requests printer capabilities.
     // |printerId|: Unique ID of the printer whose capabilities are requested.
     // |resultCallback|: Callback to return device capabilities in
     // <a href="https://developers.google.com/cloud-print/docs/cdd#cdd">CDD
     // format</a>.
     // The receiving listener must call callback exectly once.
     static void onGetCapabilityRequested(DOMString printerId,
                                          CapabilitiesCallback resultCallback);
 
     // Event fired when print manager requests printing.
     // |printJob|: The printing request parameters.
     // |resultCallback|: Callback that should be called when the printing
     // request is completed.
     static void onPrintRequested(PrintJob printJob,
                                  PrintCallback resultCallback);
   };
 };