Add WebUSB bindings and client interface

Source/modules/webusb/USBControlTransferParameters.idl

Index: Source/modules/webusb/USBControlTransferParameters.idl
diff --git a/Source/modules/webusb/USBControlTransferParameters.idl b/Source/modules/webusb/USBControlTransferParameters.idl
new file mode 100644
index 0000000000000000000000000000000000000000..98d726124c9964337940e9871d1ba3451edc9085
--- /dev/null
+++ b/Source/modules/webusb/USBControlTransferParameters.idl
@@ -0,0 +1,23 @@
+// Copyright 2015 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.
+
+enum USBRequestType {
+    "standard",
+    "class",
+    "vendor"
+};
+
+enum USBRecipient {
+    "device",
+    "interface",
+    "endpoint"
+};

[Reilly Grant (use Gerrit), 2015/07/23 23:24:08]

"other" is a valid value here.

[Ken Rockot(use gerrit already), 2015/07/28 22:30:38]

Done.

+
+dictionary USBControlTransferParameters {
+    required USBRequestType requestType;
+    required USBRecipient recipient;
+    required octet request;
+    required unsigned short value;
+    unsigned short index;

[Reilly Grant (use Gerrit), 2015/07/23 23:24:08]

The spec was updated to make this field required.

[Ken Rockot(use gerrit already), 2015/07/28 22:30:38]

Done.

+};