Add getUserSelectedDevices to the USB extensions API.

extensions/common/api/usb.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.
 
 // Use the <code>chrome.usb</code> API to interact with connected USB
 // devices. This API provides access to USB operations from within the context
 // of an app. Using this API, apps can function as drivers for hardware devices.
 //
 // Errors generated by this API are reported by setting
 // $(ref:runtime.lastError) and executing the function's regular callback. The
@@ skipping 168 matching lines @@
 
   dictionary EnumerateDevicesOptions {
     [deprecated="Equivalent to setting $(ref:DeviceFilter.vendorId)."]
     long? vendorId;
     [deprecated="Equivalent to setting $(ref:DeviceFilter.productId)."]
     long? productId;
     // A device matching any given filter will be returned. An empty filter list
     // will return all devices the app has permission for.
     DeviceFilter[]? filters;
   };
-  
+
   dictionary EnumerateDevicesAndRequestAccessOptions {
     // The device vendor ID.
     long vendorId;
     // The product ID.
     long productId;
     // The interface ID to request access to.
     // Only available on ChromeOS. It has no effect on other platforms.
     long? interfaceId;
   };
 
   callback VoidCallback = void ();
   callback GetDevicesCallback = void (Device[] devices);
   callback RequestAccessCallback = void (boolean success);
   callback OpenDeviceCallback = void (ConnectionHandle handle);
   callback FindDevicesCallback = void (ConnectionHandle[] handles);
   callback GetConfigurationCallback = void (ConfigDescriptor config);
   callback ListInterfacesCallback = void (InterfaceDescriptor[] descriptors);
   callback CloseDeviceCallback = void ();
   callback TransferCallback = void (TransferResultInfo info);
   callback ResetDeviceCallback = void(boolean success);
 
   interface Functions {
     // Enumerates connected USB devices.
     // |options|: The properties to search for on target devices.
     static void getDevices(EnumerateDevicesOptions options,
                            GetDevicesCallback callback);
 
+    // Presents a device picker to the user and returns the $(ref:Device)s
+    // selected.
+    // If the user cancels the picker devices will be empty. A user gesture
+    // is required for the dialog to display. Without a user gesture, the
+    // callback will run as though the user cancelled. If multiple filters are
+    // provided devices matching any filter will be displayed.
+    // |multiple|: Sets whether a user is allowed to select multiple devices.
+    // |filters|: Devices to present to the user.
+    // |callback|: Invoked with a list of chosen $(ref:Device)s.
+    static void getUserSelectedDevices(boolean multiple,
+                                       DeviceFilter[] filters,
+                                       GetDevicesCallback callback);
+
     // Requests access from the permission broker to a device claimed by
     // ChromeOS if the given interface on the device is not claimed.
     //
     // <b>Note:</b> This method is ChromeOS specific. Calling this method on
     // other platforms will fail.
     //
     // |device|: The $(ref:Device) to request access to.
     // |interfaceId|: The particular interface requested.
     static void requestAccess(Device device,
                               long interfaceId,
@@ skipping 103 matching lines @@
     // If the reset fails, the given connection handle will be closed and the 
     // USB device will appear to be disconnected then reconnected. 
     // In this case $(ref:getDevices) or $(ref:findDevices) must be called again
     // to acquire the device.
     //
     // |handle|: A connection handle to reset.
     static void resetDevice(ConnectionHandle handle,
                             ResetDeviceCallback callback);
   };
 };