"Like Mr. Pichai, other key Google employees, including those in leadership roles, routinely opted to move from history-on rooms to history-off Chats to hold sensitive conversations, even though they knew they were subject to legal holds"
So what? That isn't deleting chat records, it's opting not to create them in the first place. Unless there was some unusually specific court order telling them they were mandated to generate new evidence specifically to convenience the plaintiffs, or the judges decide to create new obligations via case law, Google will simply point out that they aren't under any obligation to forcibly record every employee conversation about a topic from the moment a lawsuit is filed that might involve that topic. Their obligation only extends to letting plaintiffs do discovery over whatever documentary evidence was already created.