Add missing protocol mail handler in chrome settings manually in order to for a gmail compose window to appear when clicking a mailto:xxxxxxx@xxxxx.com link on a web site.
Google Chrome
1) Click Settings
2) Scroll to the bottom and click Advanced Settings.
3) Under Privacy, click Content Settings.
4) Scroll down and click Manage Handlers.
5) If the mailto handler exists but is something other than gmail, the click the 3 dots and click Remove. If it is missing, do the following.
a) Bring up your gmail in a Chrome Tab.
b) Open the javascript console in Chrome (ctrl-shift-j) and enter the folowing:
navigator.
c)
Choose the ‘Allow’ radio button and click done.
c) Go back to your Manage Handlers and the mailto handler should now be there pointing to mail.google.com.