[CrOS] Enumerate existing mount points and check for media devices.

chrome/browser/media_gallery/media_device_notifications_chromeos.cc

Index: chrome/browser/media_gallery/media_device_notifications_chromeos.cc
diff --git a/chrome/browser/media_gallery/media_device_notifications_chromeos.cc b/chrome/browser/media_gallery/media_device_notifications_chromeos.cc
index f8bb783faee3b50d9487b42f756a8025b1451759..d2bc137342832de330c57b23151594feb26e4503 100644
--- a/chrome/browser/media_gallery/media_device_notifications_chromeos.cc
+++ b/chrome/browser/media_gallery/media_device_notifications_chromeos.cc
@@ -34,6 +34,7 @@ using content::BrowserThread;
 MediaDeviceNotifications::MediaDeviceNotifications() {
   DCHECK(disks::DiskMountManager::GetInstance());
   disks::DiskMountManager::GetInstance()->AddObserver(this);
+  CheckExistingMountPointsOnUIThread();
 }
 
 MediaDeviceNotifications::~MediaDeviceNotifications() {
@@ -43,6 +44,19 @@ MediaDeviceNotifications::~MediaDeviceNotifications() {
   }
 }
 
+void MediaDeviceNotifications::CheckExistingMountPointsOnUIThread() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  const disks::DiskMountManager::MountPointMap& mount_point_map =
+      disks::DiskMountManager::GetInstance()->mount_points();
+  for (disks::DiskMountManager::MountPointMap::const_iterator it =
+           mount_point_map.begin(); it != mount_point_map.end(); ++it) {
+    BrowserThread::PostTask(
+        BrowserThread::FILE, FROM_HERE,
+        base::Bind(&MediaDeviceNotifications::CheckMountedPathOnFileThread,
+                   this, it->second));
+  }
+}
+
 void MediaDeviceNotifications::DiskChanged(
     disks::DiskMountManagerEventType event,
     const disks::DiskMountManager::Disk* disk) {