Gmail as a default mail client in Windows.

It is possible after installing tvhgooglemapi ( http://jankeirse.github.io/tvhgooglemapi/, Java required) and setting "less secure" access of applications, to Google ie. requiring only the email address and password. https://www.google.com/settings/security/lesssecureapps

Calling a default mail client by a windows application will start the default brawser and add the created message to drafts.

For instance one can write a VBA macro in Excel that sends an email with a browser and Gmail account:  https://msdn.microsoft.com/en-us/library/office/aa203718%28v=office.11%29.aspx#odc_mailasinglesheet  ...