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

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index d569188984f2990471f5a3e1833af4474798da6b..519442943ae9abc8600f72319c07a9519dbbe322 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -909,6 +909,13 @@ void BrowserMainLoop::ShutdownThreadsAndCleanUp() {
   }
 }
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+void BrowserMainLoop::StartMonitoring() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  device_monitor_mac_->StartMonitoring();
+}
+#endif
+
 void BrowserMainLoop::InitializeMainThread() {
   TRACE_EVENT0("startup", "BrowserMainLoop::InitializeMainThread")
   const char* kThreadName = "CrBrowserMain";