Is it misconduct for a prosecutor to act as his own expert witness?

Defendant asserts that it was misconduct for the prosecutor to act as his own expert witness by presenting his own opinions about "the 'open and shut' nature of real-life criminal cases" and for him to appeal to the jurors' passions by suggesting that defendant had confessed and the trial was waste of the jurors' time. "[I]t is misconduct for prosecutors to vouch for the strength of their cases by invoking their personal prestige, reputation, or depth of experience, or the prestige or reputation of their office, in support of it. [Citations.] Specifically, a prosecutor's reference to his or her own experience, comparing a defendant's case negatively to others the prosecutor knows about or has tried, is improper. [Citation.] Nor may prosecutors offer their personal opinions when they are based solely on their experience or on other facts outside the record. [Citations.]" (People v. Huggins (2006) 38 Cal.4th 175, 206-207 (Huggins).)