http://www.mattcutts.com/blog/disclosure/

    Also, I have invested in Perfect Third (the company that 
    makes the WakeMate), Zencoder, Cardpool, Tasty Labs,
    Drchrono, Grubwithus, PoundPay, Apportable, Mailgun, and 
    Parse. I have also invested in CircuitHub, PlanGrid, 
    Pixelapse, ZenPayroll, Trigger.io, Zenefits, and True
    Link Financial.

    I have also invested in Lowercase Capital (Lowercase 
    Ventures Fund I), Y Combinator (Y Combinator Fund II), 
    Lowercase 140, and Lowercase Spur.

Pretty reasonable to assume RG enjoyed a direct line to Cutts all through the entire thing.

X is an investor, therefore X must be directly persuaded by Y investor?

That's not any evidence that RG specifically had a direct line to Cutts, and that this actually influenced the outcome. Again, we're talking about someone who penalized Chrome. I don't know of any greater conflict of interest than your employer.

In an argument about someone's motivations, I am inclined to give them the benefit of the doubt in the context of their past behavior.

I'm inclined to believe that savvy investors would leverage their own investors and network to solve problems when they can. Especially when X is an investor in Y.

The incredibly fast timeline is pretty clear evidence of communication considering the standard response time is never and the standard unpunishing time is never and the standard result is basically "change your domain".