HID: Support top-level collection usages in device info.

chrome/common/extensions/api/hid.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.hid</code> API to interact with connected HID devices.
 // This API provides access to HID operations from within the context of an app.
 // Using this API, apps can function as drivers for hardware devices.
 namespace hid {
 
+  // HID usage pair.
+  // |usage_page|: HID usage page.
+  // |usage|: HID usage.
+  dictionary HidUsageAndPage {
+    long usage_page;
+    long usage;
+  };
+
   // Returned by <code>getDevices</code> functions to describes a connected HID
   // device. Use <code>connect</code> to connect to any of the returned devices.
+  // |deviceId|: Device opaque ID.
+  // |vendorId|: Vendor ID.
+  // |productId|: Product ID.
+  // |usages|: HID usage pairs exposed by underlying Top-level collections.
   dictionary HidDeviceInfo {
     long deviceId;
     long vendorId;
     long productId;
+    HidUsageAndPage[] usages;
   };
 
   // Returned by <code>connect</code> to represent a communication session with
   // an HID device. Must be closed with a call to <code>disconnect</code>.
   dictionary HidConnectInfo {
     long connectionId;
   };
 
   // Searching criteria to enumerate devices with.
   dictionary GetDevicesOptions {
@@ skipping 74 matching lines @@
     // |connectionId|: The connection to read Input report from.
     // |reportId|: The report ID to use, or <code>0</code> if none.
     // |data|: The report data.
     // |callback|: The callback to invoke once the write is finished.
     static void sendFeatureReport(long connectionId,
                                   long reportId,
                                   ArrayBuffer data,
                                   SendCallback callback);
   };
 };