What is the test for determining whether a cause of action arises from protected speech or petitioning activity?

The first step of the analysis thus turns on the conduct underlying the allegations of the complaint. "Determining whether a cause of action arises from protected speech or petitioning activity requires a focus on the principal thrust or gravamen of the cause of action. If the allegations of protected activity are merely incidental to a cause of action based essentially on nonprotected activity, the allegations will not transform the nonprotected cause of action into an action subject to the anti-SLAPP law. [Citations.] The focus on the gravamen of the action does not implicate 'some philosophical thrust or legal essence of the cause of action.' [Citation.] Instead, courts are to focus on the acts on which liability is alleged to be based. [Citation.]" (People ex rel. Fire Insurance Exchange v. Anapol (2012) 211 Cal.App.4th 809, 823 (Anapol).) " 'The defendant need not prove that the challenged conduct is protected by the First Amendment as a matter of law; only a prima facie showing is required.' [Citation.]" (Id. at p. 822.)