"Only need to show one"
Go lookup what Googles 'de minimis' affirmative defence means... *amount* of copying *does* matter and 1 case of 9 lines in 15million seems a pretty good candidate for de minimis.
Particularly when the copied function is also a good example of unprotectable code - on grounds that you can't implement it in any functionally different way and that's its function and use is required to fulfil the Sort method contract.
I expect de minimis will cover the test suite files HP smuggled into the tree as well, on the basis they had no actual use or value to Android.
US software copyright law is not as simple as most of you seem to believe. It's messy, looks unfair (multiple ways to get away with copying for instance) largely because it evolved to prevent a whole family of abuses by copyright holders. There's a reason Oracle are trying to create new law here, the existing precedents don't support their claims.
Sun wove a contractual web designed to lockin control of Java but failed to cover all loopholes.