There used to be an item known as Gmail Notifier for Mac, and this recently (last week) was discontinued by google; citing their browser was their answer. Or an add-on to an existing supported browser that could allow you to see gmail when already online in a browser.
Follow the instructions below to see how you can upload files from your Mac’s Finder to Gmail with just one click. I use Dropbox on a daily basis, but I don’t want to store all my files in it: sure, I got 6 GB for free with the referral system, but I don’t want to waste space. There used to be an item known as Gmail Notifier for Mac, and this recently (last week) was discontinued by google; citing their browser was their answer. Or an add-on to an existing supported browser that could allow you to see gmail when already online in a browser.
Neither of these were suitable for my older Macs (pre Snow Leopard) but I already had a Google Notifier version in each of my Macs. And I had locked the application prior to announcements of its demise.
While they did discontinue the product and the numbered notification function in Notifier, I was able to use Notifier preferences to disable the automatic features yet still use the icon in the main Menu to still access my logged-in Gmail account. The icon allows access to gmail and calendars, via my google account.
Also I no longer get their final notice email, having figured out a sequence while logged in (final notice appears in a separate window than regular gmail) and as I use a dedicated browser set as default to the System, I still use the gmail as a web-based service; not download into Mail.
The final notice will return if you turn back on active Notifier
function (checkbox) in Notifier preferences, however.
You may not be able to download the Notifier anymore, and I would suspect an offer to get it online may be from some untoward source of adware or some other unwanted attribute some sites will load along with the bait.
Gmail
A few third-party notifier-like items had been announced but I wonder if they also don't use their version to harvest information on your online activities, since you have to blindly trust whoever they say they are.
So I am not certain of your choices or their reliability, or reputation.