Patch to Google Chrome launcher to match window title properly. See http://kb.openstudioproject.com/content/fix-double-google-chrome-icon-docky-and-plank

google-chrome.desktop.patch

--- original/google-chrome.desktop
+++ fixed/google-chrome.desktop
@@ -112,6 +112,7 @@
 Categories=Network;WebBrowser;
 MimeType=text/html;text/xml;application/xhtml_xml;image/webp;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/ftp;
 X-Ayatana-Desktop-Shortcuts=NewWindow;NewIncognito
+StartupWMClass=Google-chrome-stable
 
 [NewWindow Shortcut Group]
 Name=New Window
@@ -167,6 +168,7 @@
 Name[zh_TW]=開新視窗
 Exec=/usr/bin/google-chrome-stable
 TargetEnvironment=Unity
+StartupWMClass=Google-chrome-stable
 
 [NewIncognito Shortcut Group]
 Name=New Incognito Window
@@ -220,3 +222,4 @@
 Name[zh_TW]=新增無痕式視窗
 Exec=/usr/bin/google-chrome-stable --incognito
 TargetEnvironment=Unity
+StartupWMClass=Google-chrome-stable