unity launcher icon display is incorrect

[Taihsiang Ho]

Ubuntu Xenial daily build (built on Apr. 07)
Dell XPS (CID 201508-18805)

Steps to reproduce this bug:
prepare a live usb and boot to live desktop.
After installing the system with a live usb, the desktop shows the same issue as well.

Expected result:
the icon display looks good and smooth.

Actual result:
please see the attachment for screenshot.

-------------

More info:
14.04.4 live usb could reproduce this issue as well.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-17.33-generic 4.4.6
Uname: Linux 4.4.0-17-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.20.1-0ubuntu1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Mon Apr 11 20:46:14 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
DkmsStatus:
 fwts-efi-runtime-dkms, 16.03.00, 4.4.0-17-generic, x86_64: installed
 tp-smapi, 0.41, 4.4.0-17-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Sky Lake Integrated Graphics [8086:1926] (rev 03) (prog-if 00 [VGA controller])
   Subsystem: Dell Skylake Integrated Graphics [1028:0704]
InstallationDate: Installed on 2016-04-08 (3 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Beta amd64 (20160407)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 004: ID 0bda:5682 Realtek Semiconductor Corp.
 Bus 001 Device 003: ID 04f3:20d0 Elan Microelectronics Corp.
 Bus 001 Device 002: ID 0a5c:6412 Broadcom Corp.
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Dell Inc. XPS 13 9350
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-17-generic.efi.signed root=UUID=085b4d0f-c1e4-4c24-8e1c-b83e73e40737 ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/08/2016
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.2.3
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.2.3:bd01/08/2016:svnDellInc.:pnXPS139350:pvr:rvnDellInc.:rn:rvr:cvnDellInc.:ct9:cvr:
dmi.product.name: XPS 13 9350
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.12.2+16.04.20160331-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.6.1-1ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Mon Apr 11 20:42:37 2016
xserver.configfile: default
xserver.errors:
 Error compiling keymap (server-844CE2B1634E5169F59C82995F96DEDC6FD2D6AF)
 XKB: Couldn't compile keymap
 Error compiling keymap (server-844CE2B1634E5169F59C82995F96DEDC6FD2D6AF)
 XKB: Couldn't compile keymap
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 5194
 vendor SHP
xserver.version: 2:1.18.3-1ubuntu1