Add a section to Site Settings listing USB devices.

chrome/android/java/src/org/chromium/chrome/browser/preferences/website/UsbInfo.java

 // Copyright 2016 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.
 
 package org.chromium.chrome.browser.preferences.website;
 
 import java.io.Serializable;
 
 /**
  * USB device information for a given origin.
+ *
+ * These objects are compared only by the identity of the device, not by which site has permission
+ * to access it.
  */
 public class UsbInfo implements Serializable {
     private final String mOrigin;
     private final String mEmbedder;
     private final String mName;
     private final String mObject;
 
     UsbInfo(String origin, String embedder, String name, String object) {
         mOrigin = origin;
         mEmbedder = embedder;
@@ skipping 16 matching lines @@
     }
 
     /**
      * Returns the name of the USB device for display in the UI.
      */
     public String getName() {
         return mName;
     }
 
     /**
+     * Returns the opaque object string that represents the device.
+     */
+    public String getObject() {
+        return mObject;
+    }
+
+    /**
      * Revokes permission for the origin to access the USB device.
      */
     public void revoke() {
         WebsitePreferenceBridge.nativeRevokeUsbPermission(mOrigin, mEmbedder, mObject);
     }
 }