Implement Linux media notifier.

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
===================================================================
--- content/browser/browser_main_loop.cc	(revision 124819)
+++ content/browser/browser_main_loop.cc	(working copy)
@@ -4,6 +4,8 @@
 
 #include "content/browser/browser_main_loop.h"
 
+#include <string>

[jam, 2012/03/06 21:21:38]

nit: no need. i understand you're adding it for IWYU, but this is such a base
include file

[Lei Zhang, 2012/03/06 21:36:50]

Done.

+
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ -54,6 +56,10 @@
 #include "net/base/winsock_init.h"
 #endif
 
+#if defined(OS_LINUX)
+#include "content/browser/media_device_notifications_linux.h"
+#endif
+
 #if defined(OS_LINUX) || defined(OS_OPENBSD)
 #include <glib-object.h>
 #endif
@@ -204,7 +210,7 @@
   return g_current_browser_main_loop->audio_manager_.get();
 }
 
-// BrowserMainLoop construction / destructione =============================
+// BrowserMainLoop construction / destruction =============================
 
 BrowserMainLoop::BrowserMainLoop(const content::MainFunctionParams& parameters)
     : parameters_(parameters),
@@ -587,6 +593,17 @@
 void BrowserMainLoop::BrowserThreadsStarted() {
   // RDH needs the IO thread to be created.
   resource_dispatcher_host_.reset(new ResourceDispatcherHost());
+
+#if defined(OS_LINUX)
+  // MediaDeviceNotificationsLinux needs the File Thread.
+  const FilePath kDefaultMtabPath("/etc/mtab");
+  media_device_notifications_linux_ =
+      new MediaDeviceNotificationsLinux(kDefaultMtabPath);
+  BrowserThread::PostTask(
+      BrowserThread::FILE, FROM_HERE,

[jam, 2012/03/06 21:21:38]

nit: it's nicer if this class can do its thread initialization itself, to keep
BrowserMainLoop small and not have to worry about implementation details. this
class can just call an Init() method that internally does this

[Lei Zhang, 2012/03/06 21:36:50]

Done.

[jam, 2012/03/06 22:22:11]

you have do it in in a separate method, i.e. after the calling code has a
reference. otherwise if the task runs on the file thread before the constructor
returns, the object will be deleted.

if you try this in debug builds, it'll crash right away because the PostTask
will do release/addref first

[Lei Zhang, 2012/03/06 23:23:42]

Oh thanks for reminding me about that. Fixed.

+      base::Bind(&MediaDeviceNotificationsLinux::InitOnFileThread,
+                 media_device_notifications_linux_.get()));
+#endif
 }
 
 void BrowserMainLoop::InitializeToolkit() {