What is the test for successfully challenging a conviction on grounds of ineffective assistance of counsel?

challenging a conviction on grounds of ineffective assistance, the defendant must demonstrate counsel's inadequacy. To satisfy this burden, the defendant must first show counsel's performance was deficient, in that it fell below an objective standard of reasonableness under prevailing professional norms. Second, the defendant must show resulting prejudice, i.e., a reasonable probability that, but for counsel's deficient performance, the outcome of the proceeding would have been different." (Ibid.) "[A] defendant claiming ineffective representation 'must show ... that counsel's deficient performance . . . "so undermined the proper functioning of the adversarial process that the trial cannot be relied on as having produced a just result." [Citations.]'" (People v. Mendoza (2000) 24 Cal.4th 130, 158.)

In reviewing claims of ineffective assistance of counsel, we presume "'that counsel's performance fell within the wide range of professional competence and that counsel's actions and inactions can be explained as a matter of sound trial strategy.' " (People v. Gamache (2010) 48 Cal.4th 347, 391.) "'Defendant thus bears the burden of establishing constitutionally inadequate assistance of counsel.'" (Ibid.) "'If the record on appeal sheds no light on why counsel acted or failed to act in the manner challenged, an appellate claim of ineffective assistance of counsel must be rejected unless counsel was asked for an explanation and failed to provide one, or there simply could be no satisfactory explanation.'" (Ibid.)