Add support for isochronous transfers in WebUSB.

third_party/WebKit/public/platform/modules/webusb/WebUSBTransferInfo.h

 // 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.
 
 #ifndef WebUSBTransferInfo_h
 #define WebUSBTransferInfo_h
 
 #include "public/platform/WebVector.h"
 
 namespace blink {
 
 struct WebUSBTransferInfo {
     enum class Status {
         Ok,
         Stall,
         Babble,
     };
 
     WebUSBTransferInfo()
-        : status(Status::Ok)
-        , bytesWritten(0)
     {
     }
 
-    Status status;
+    // Individual packet statuses. This vector has only one element if this was

[Ken Rockot(use gerrit already), 2016/02/03 14:19:10]

nit: why past tense "was"? it may have happened or may be about to happen, but
*it* "is" a transfer

+    // not an isochronous transfer.
+    WebVector<Status> status;
 
     // Data received, if this is an inbound transfer.
     WebVector<uint8_t> data;
 
-    // Number of bytes written if this is an outbound transfer.
-    uint32_t bytesWritten;
+    // Requested length of each packet if this was an inbound isochronous
+    // transfer.
+    WebVector<uint32_t> packetLength;
+
+    // Number of bytes written if this is an outbound transfer. This vector has
+    // only one element if this was not an isochronous transfer otherwise it is
+    // the number of bytes transferred in each isochronous packet (inbound or
+    // outbound).
+    WebVector<uint32_t> bytesTransferred;
 };
 
 } // namespace blink
 
 #endif // WebUSBTransferInfo_h