Add chrome.hid.getUserSelectedDevices API.

extensions/common/api/hid.idl

Index: extensions/common/api/hid.idl
diff --git a/extensions/common/api/hid.idl b/extensions/common/api/hid.idl
index f695176669c2b50cd40990c2be8e4edcc4d193e8..48aaf38e9864f4f293ef35a0a6de719abbec3556 100644
--- a/extensions/common/api/hid.idl
+++ b/extensions/common/api/hid.idl
@@ -64,6 +64,14 @@ namespace hid {
     DeviceFilter[]? filters;
   };
 
+  dictionary DevicePromptOptions {
+    // Allow the user to select multiple devices.
+    boolean? multiple;
+    // Filter the list of devices presented to the user. If multiple filters
+    // are provided devices matching any filter will be displayed.
+    DeviceFilter[]? filters;
+  };
+
   callback GetDevicesCallback = void (HidDeviceInfo[] devices);
   callback ConnectCallback = void (HidConnectInfo connection);
   callback DisconnectCallback = void ();
@@ -84,6 +92,17 @@ namespace hid {
     static void getDevices(GetDevicesOptions options,
                            GetDevicesCallback callback);
 
+    // Presents a device picker to the user and returns $(ref:HidDeviceInfo)
+    // objects for the devices 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.
+    // |options|: Configuration of the device picker dialog box.
+    // |callback|: Invoked with a list of chosen $(ref:Device)s.
+    static void getUserSelectedDevices(optional DevicePromptOptions options,
+                                       GetDevicesCallback callback);
+
     // Open a connection to an HID device for communication.
     // |deviceId|: The $(ref:HidDeviceInfo.deviceId) of the device to open.
     static void connect(long deviceId,