Does the CD show up on the desktop or in nautilus when you insert it?  If not, try running 'devkit-disks --poll-for-media /dev/cdrom' (replace /dev/cdrom with your actual device).  If that works, it's a devicekit-disks problem.

The original reporter was already asked this by another triager, and the CD-ROM drive shows up in nautilus. 
Here is the cdrom drive information from the udev log, don't know if it will make a difference:

P: /devices/pci0000:00/0000:00:14.1/host1/target1:0:0/1:0:0:0/block/sr0
N: sr0
S: block/11:0
S: scd0
S: disk/by-path/pci-0000:00:14.1-scsi-1:0:0:0
S: cdrom
S: cdrw
S: dvd
S: dvdrw
E: UDEV_LOG=3
E: DEVPATH=/devices/pci0000:00/0000:00:14.1/host1/target1:0:0/1:0:0:0/block/sr0
E: MAJOR=11
E: MINOR=0
E: DEVNAME=/dev/sr0
E: DEVTYPE=disk
E: SUBSYSTEM=block
E: ID_CDROM=1
E: ID_CDROM_MRW=1
E: ID_CDROM_MRW_W=1
E: ID_CDROM_MEDIA=1
E: ID_VENDOR=COMPAQ
E: ID_VENDOR_ENC=COMPAQ\x20\x20
E: ID_MODEL=CD-ROM_CRD-8484B
E: ID_MODEL_ENC=CD-ROM\x20CRD-8484B
E: ID_REVISION=1.04
E: ID_TYPE=cd
E: ID_BUS=scsi
E: ID_PATH=pci-0000:00:14.1-scsi-1:0:0:0
E: ACL_MANAGE=1
E: GENERATED=1
E: DKD_MEDIA_AVAILABLE=1
E: DKD_PRESENTATION_NOPOLICY=0
E: DEVLINKS=/dev/block/11:0 /dev/scd0 /dev/disk/by-path/pci-0000:00:14.1-scsi-1:0:0:0 /dev/cdrom /dev/cdrw /dev/dvd /dev/dvdrw

Output from 'rhythmbox -d' during insertion of an audio CD would probably help.

Udev logs are not relevant here.

Created attachment 152355 [details]
rhythmbox -d

Here is what the original reporter has supplied re: "rhythmbox -d" if it is insufficient, please let me know.

I am the other triager for the Launchpad bug report.

The OR attempted to do a "Import File..." to load the CD in Rhythmbox, but the CD was not available for selecting in the file browser.  Therefore, I believe the CD is NOT visible in Nautilus.  The OR reported being able to select the CD from Nautilus in a previous version of Ubuntu, but now it no longer appears.

Rhythmbox isn't getting any kind of notification of the CD being inserted or mounted.  The problem is in nautilus, gvfs, or devkit-disks.

Output from 'gvfs-mount -li' before and after inserting a CD might help.

The OR has ran the requested command with some very interesting results.  As you will see below, gvfs has the CD drive listed when there is no CD.  However, when a Music CD gets inserted, the CD drive listing disappears.

Before CD insertion:

doris@doris-desktop:~$ gvfs-mount -li
Drive(0): Floppy Drive
  Type: GProxyDrive (GProxyVolumeMonitorGdu)
  ids:
   unix-device: '/dev/fd0'
  themed icons:  [drive-removable-media-floppy]  [drive-removable-media]  [drive-removable]  [drive]
  is_media_removable=1
  has_media=0
  is_media_check_automatic=0
  can_poll_for_media=1
  can_eject=0
  can_start=0
  can_stop=0
  start_stop_type=unknown
Drive(1): CD Drive
  Type: GProxyDrive (GProxyVolumeMonitorGdu)
  ids:
   unix-device: '/dev/sr0'
  themed icons:  [drive-optical]  [drive]
  is_media_removable=1
  has_media=0
  is_media_check_automatic=1
  can_poll_for_media=1
  can_eject=0
  can_start=0
  can_stop=0
  start_stop_type=unknown



After CD insertion:

doris@doris-desktop:~$ gvfs-mount -li
Drive(0): Floppy Drive
  Type: GProxyDrive (GProxyVolumeMonitorGdu)
  ids:
   unix-device: '/dev/fd0'
  themed icons:  [drive-removable-media-floppy]  [drive-removable-media]  [drive-removable]  [drive]
  is_media_removable=1
  has_media=0
  is_media_check_automatic=0
  can_poll_for_media=1
  can_eject=0
  can_start=0
  can_stop=0
  start_stop_type=unknown

I think you'd be best off working on this in the downstream bug report until you work out where the problem actually is.  I don't know where to look next.