Add more generic filters to the chrome.hid.getDevices API.

extensions/common/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 top-level collection attributes.
   // Each enumerated device interface exposes an array of these objects.
@@ skipping 24 matching lines @@
     long maxOutputReportSize;
     long maxFeatureReportSize;
   };
 
   // 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.
+  // Device matching criteria.
+  dictionary DeviceFilter {
+    long? vendorId;
+    // (checked only if the vendor ID matches)
+    long? productId;
+    long? usagePage;
+    // (checked only if the HID usage page matches)

[not at google - send to devlin, 2014/08/29 00:26:26]

This is all going to be generated as https://developer.chrome.com/apps/hid -
these comment in parenthesis are useful but would look better as part of a whole
document.

I don't know much about this stuff, but it seems like if certain properties are
only checked in certain conditions... this filter is a match-everything-specific
type thing?

+    long? usage;
+  };
+
+  // Options passed to <code>getDevices</code>.
   dictionary GetDevicesOptions {
-    long vendorId;
-    long productId;
+    // <b>Note:</b> Deprecated, equivalent to a filter with
+    // <code>vendorId</code> set.
+    long? vendorId;

[not at google - send to devlin, 2014/08/29 00:26:26]

There's a deprecated annotation:

[deprecated=Use a filter with $(ref:hid.DeviceFilter.vendorId vendorId)]

likewise.

+    // <b>Note:</b> Deprecated, equivalent to a filter with
+    // <code>productId</code> set.
+    long? productId;
+    // Devices matching any of the given filters will be returned. Providing an
+    // empty filter list will return all devices the app has permission for.
+    DeviceFilter[]? filters;
   };
 
   callback GetDevicesCallback = void (HidDeviceInfo[] devices);
   callback ConnectCallback = void (HidConnectInfo connection);
   callback DisconnectCallback = void ();
 
   // The callback to be invoked when a <code>receive</code> call is finished.
   // |reportId|: The ID of the report.
   // |data|: The content of the report.
   callback ReceiveCallback = void (long reportId, ArrayBuffer data);
 
   // The callback to be invoked when a <code>receiveFeatureReport</code> call
   // is finished.
   // |data|: The content of the report.
   callback ReceiveFeatureReportCallback = void (ArrayBuffer data);
 
   // The callback to be invoked when a <code>send</code> or
   // <code>sendFeatureReport</code> call is finished.
   callback SendCallback = void();
 
   interface Functions {
-    // Enumerate all the connected HID devices specified by the vendorId/
-    // productId/interfaceId tuple.
+    // Enumerate all the connected HID devices matching the given properties.
     // |options|: The properties to search for on target devices.
     // |callback|: Invoked with the <code>HidDeviceInfo</code> array on success.
     static void getDevices(GetDevicesOptions options,
                            GetDevicesCallback callback);
 
     // Open a connection to an HID device for communication.
     // |deviceId|: The ID of the device to open.
     // |callback|: Invoked with an <code>HidConnectInfo</code>.
     static void connect(long deviceId,
                         ConnectCallback callback);
@@ skipping 43 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);
   };
 };