Mac AVFoundation/QTKit: delay DeviceMonitorMac startup to first GetUserMedia.

content/browser/renderer_host/media/media_stream_manager.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_manager.h"
 
 #include <list>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/rand_util.h"
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread.h"
 #include "content/browser/browser_main_loop.h"
+#include "content/browser/device_monitor_mac.h"
 #include "content/browser/media/capture/web_contents_capture_util.h"
 #include "content/browser/renderer_host/media/audio_input_device_manager.h"
 #include "content/browser/renderer_host/media/device_request_message_filter.h"
 #include "content/browser/renderer_host/media/media_stream_requester.h"
 #include "content/browser/renderer_host/media/media_stream_ui_proxy.h"
 #include "content/browser/renderer_host/media/video_capture_manager.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/media_device_id.h"
@@ skipping 748 matching lines @@
 
   monitoring_started_ = true;
   base::SystemMonitor::Get()->AddDevicesChangedObserver(this);
 
   // Enumerate both the audio and video devices to cache the device lists
   // and send them to media observer.
   ++active_enumeration_ref_count_[MEDIA_DEVICE_AUDIO_CAPTURE];
   audio_input_device_manager_->EnumerateDevices(MEDIA_DEVICE_AUDIO_CAPTURE);
   ++active_enumeration_ref_count_[MEDIA_DEVICE_VIDEO_CAPTURE];
   video_capture_manager_->EnumerateDevices(MEDIA_DEVICE_VIDEO_CAPTURE);
+
+#if defined(OS_MACOSX)
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&MediaStreamManager::StartMonitoringOnUIThread,
+                 base::Unretained(this)));
+#endif
 }
 
+#if defined(OS_MACOSX)
+void MediaStreamManager::StartMonitoringOnUIThread() {

[Robert Sesek, 2014/03/10 17:22:46]

DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

[mcasas, 2014/03/10 18:19:45]

Done.

+  if (content::BrowserMainLoop::GetInstance()) {
+    BrowserThread::PostTask(

[Robert Sesek, 2014/03/10 17:22:46]

Why do you need to post a task to do this?

[mcasas, 2014/03/10 18:19:45]

Not needed now with the accessor device_monitor_mac().

+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&BrowserMainLoop::StartMonitoring,
+                   base::Unretained(content::BrowserMainLoop::GetInstance())));
+  }
+}
+#endif
+
 void MediaStreamManager::StopMonitoring() {
   DCHECK_EQ(base::MessageLoop::current(), io_loop_);
   if (monitoring_started_) {
     base::SystemMonitor::Get()->RemoveDevicesChangedObserver(this);
     monitoring_started_ = false;
     ClearEnumerationCache(&audio_enumeration_cache_);
     ClearEnumerationCache(&video_enumeration_cache_);
   }
 }
 
@@ skipping 1017 matching lines @@
   }
 
   // Always do enumeration even though some enumeration is in progress,
   // because those enumeration commands could be sent before these devices
   // change.
   ++active_enumeration_ref_count_[stream_type];
   GetDeviceManager(stream_type)->EnumerateDevices(stream_type);
 }
 
 }  // namespace content