ajax fails in chrome extension when deployed in a google product like docs or gmail

Question

Hi there fellow exchangers!

I am creating a chrome extension that appears above the website a user is viewing. I want to pull and send data to a database located on a server. I know that I'll be using xhr and while this works across the web...it oddly fails when I try and deploy this code on sites that are google products, such as gmail and google docs. It almost seems like google prevents XMLHttpRequest around their sites/products. Ironically enough, those are the two sites that I care the most that this works on. Any insight on why CORS behaves differently on the .google.com/ domain or what I'm missing would be greatly appreciated it.

$.ajax({
    url: urlpath + "db.php?type=symbol&value=",
    type: 'GET',
    data: "{}",
    contentType: "application/json; charset=utf-8",
    dataType: 'json',
    async: false,
    success: function(data){
        db = data;
    },
    error : function () {
        alert('DB connection failed');
    }
});

Here's what my manifest.json file has for permissions (I also have the matches for good measure):

{
  "name": "My extension",
  ...
  "permissions": [
    "http://*/*",
    "https://*/*"
  ],
  ...
  "content_scripts": [ {
   ...
       "matches": [ 
   "http://*/*", "https://*/*", 
    "https://mail.google.com/mail/*", "http://mail.google.com/mail/*",
    "https://mail.google.com/*", "http://mail.google.com/*"
        ]
  }]
}