What is the test for establishing a cause of action arising from a speech?

"[T]he statutory phrase 'cause of action . . . arising from' means simply that the defendant's act underlying the plaintiff's cause of action must itself have been an act in furtherance of the right of petition or free speech. [Citation.] . . . [T]he critical point is whether the plaintiff's cause of action itself was based on an act in furtherance of the defendant's right of petition or free speech. [Citations.] 'A defendant meets this burden by demonstrating that the act underlying the plaintiff's cause fits one of the categories spelled out in section 425.16, subdivision (e) . . . . ' [Citations.]" (City of Cotati v. Cashman (2002) 29 Cal.4th 69, 78 (City of Cotati).)