refactor EnumerateDevices to make it a persistent request.

content/browser/renderer_host/media/media_stream_dispatcher_host.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/browser/renderer_host/media/media_stream_dispatcher_host.h"
 
 #include "content/browser/browser_main_loop.h"
 #include "content/common/media/media_stream_messages.h"
 #include "content/common/media/media_stream_options.h"
 #include "googleurl/src/gurl.h"
@@ skipping 82 matching lines @@
 void MediaStreamDispatcherHost::DevicesEnumerated(
     const std::string& label,
     const StreamDeviceInfoArray& devices) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DVLOG(1) << "MediaStreamDispatcherHost::DevicesEnumerated("
            << ", {label = " << label <<  "})";
 
   StreamMap::iterator it = streams_.find(label);
   DCHECK(it != streams_.end());
   StreamRequest request = it->second;
-  streams_.erase(it);
 
   Send(new MediaStreamMsg_DevicesEnumerated(
-      request.render_view_id, request.page_request_id, devices));
+      request.render_view_id, request.page_request_id, label, devices));
 }
 
 void MediaStreamDispatcherHost::DevicesEnumerationFailed(
     const std::string& label) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DVLOG(1) << "MediaStreamDispatcherHost::DevicesEnumerationFailed("
            << ", {label = " << label <<  "})";
 
   StreamMap::iterator it = streams_.find(label);
   DCHECK(it != streams_.end());
@@ skipping 150 matching lines @@
                         device_id, type, security_origin, &label);
   DCHECK(!label.empty());
   streams_[label] = StreamRequest(render_view_id, page_request_id);
 }
 
 MediaStreamManager* MediaStreamDispatcherHost::GetManager() {
   return BrowserMainLoop::GetMediaStreamManager();
 }
 
 }  // namespace media_stream