UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36

Steps to reproduce the problem:
1.How to Connect Google Spreadsheet from Chrome extesntion (if not possible directly then How to connect API's)
2.How to Fetch Data from Google Spreadsheet from Chrome extesntion 
3.How to Insert Data from Google Spreadsheet from Chrome extesntion  

What is the expected behavior?
Currently Getting Unauthorized Access/Access Denied

What went wrong?
Mixed Content: The page at 'https://jsfiddle.net/L5p1yvpa/' was loaded over HTTPS, but requested an insecure script 'http://spreadsheets.google.com/feeds/list/0AlO_LanGCFltdGlsa2hSNHhOdHlCYmpFeXdlY0ZNS2c/od6/public/values?alt=json-in-script&callback=displayContent'. This request has been blocked; the content must be served over HTTPS.

Did this work before? N/A 

Does this work in other browsers? N/A

Chrome version: 55.0.2883.87  Channel: stable
OS Version: 10.0
Flash Version: