Implement a salt for MediaSource IDs that can be cleared by a user.

content/browser/media_devices_monitor.cc

 // Copyright (c) 2012 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.
 
 #include "content/public/browser/media_devices_monitor.h"
 
 #include "content/browser/browser_main_loop.h"
 #include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace content {
 namespace {
 void EnsureMonitorCaptureDevicesInternal(
     MediaStreamManager* media_stream_manager) {
   media_stream_manager->EnumerateDevices(
-      NULL, -1, -1, -1, MEDIA_DEVICE_AUDIO_CAPTURE, GURL());
+      NULL, -1, -1, NULL, -1, MEDIA_DEVICE_AUDIO_CAPTURE, GURL());
 }
 }
 
 void EnsureMonitorCaptureDevices() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&EnsureMonitorCaptureDevicesInternal,
                  BrowserMainLoop::GetInstance()->media_stream_manager()));
 }
 
 }  // namespace content