how to use Spreadsheets API and Documents List API at the same time

[Shih-Ling Keng]

My case is that I want to check if a specific spreadsheet exists, if yes, 
use Spreadsheets API to add a row, otherwise, use Documents List API to 
create one, and then use Spreadsheets API to add a row.

My first idea is calling ChromeExOAuth.initBackgroundPage in background.html 
twice:

var oauth = ChromeExOAuth.initBackgroundPage({
...
'scope': 'https://spreadsheets.google.com/feeds',
...

var oauth2 = ChromeExOAuth.initBackgroundPage({
...
'scope': 'https://docs.google.com/feeds',
...

But when I call bgPage.oauth2.authorize(), it goes into infinite loop and 
keeps opening new tabs with empty content. 

After trying to google solutions, I realized that I should not 
call initBackgroundPage() twice, but I can't find a correct way to use both 
API at the same time.

Any comment is highly appreciated.

Thanks